I really think the Champion dorks are really strong. I just have way better luck with them it seems, see my above experience. Galvanizer is really bad outside that combo. I've almost never drawn him and the times that I have it usually rapidly lets me combo off. I'll put him higher on my watch list though, because he is really terrible in a vacuum.
TBF I never really played with the Champion dorks much; I goldfished the deck a couple times and they were consistently awkward and not very useful to cast so I cut them early on in testing. I did recently manage to protect a creature from a wrath (ironically a Crux of Fate) by tutoring up my one Champion dork to protect it, but that's a play I can't see making more than once in a game generally speaking. I'll pay attention to how often I want to tutor them up in the future. My other issue with Galvanizer, aside from half its use being with combo, is its other main use is generating lots of mana and cards with things like Manaweft Sliver or Azami, but generally speaking when I have one of those cards + a couple of changelings the deck is already performing extremely well, so it feels a bit win-more.
Ironically, I had someone play Crux of Fate against me naming dragons. I think my meta-game is a bit less creature reliant, I'm pretty comfortable with the two wrath spells I'm running. Crux of Fate is great, but I have a ton of dragon cards already. :/
The meta I play this deck in generally has a lot of "fair" creature decks so it's important for me to have an answer to a scary board at some point or another. I only just put the Avatar in so no idea how it plays yet; half the reason I'm running it is just to check off Dinosaur. :>
Personally I'm thinking of cutting Sliver Overlord. I find casting it, paying 3 mana and then the casting cost of a sliver to be prohibitively slow. The only thing I ever really wanted to search for was Sliver Hivelord which I cut.
For me Hivelord has been pretty great, granted the couples times I drew it I also had a mana dork to help activate it quickly. It also has some amazing tutor targets. Hibernation Sliver has been one of the best cards in the deck for me, protecting me from wraths, working well with ETBs, and of course being a combo piece. Harmonic Sliver has been key to stopping some shenanigans. I also run a slightly bigger Sliver package with Cloudshredder Sliver. Being a big 7/7 is also nice for holding off attacks or attacking itself. If your meta is faster it might be a reasonable cut though.
Patriarch's Bidding and Coat of Arms seem great, I'm just worried about the fact that they benefit everyone. I think other people might get more use out of casting them than I do. My metagame has a bunch of graveyard abuse decks and token swarms are always popular. This is the primary reason I hadn't added them myself.
I played a game recently where another player at the table played Coat of Arms, and that was enough to convince me it probably doesn't belong in my deck. There's too many ways for other players to have more creature than me since the deck doesn't really make tokens, and me having 2 or 3 15/15s isn't as good as someone having 8 10/10s.
I'm also planning on porting this over to mtgNexus in the near future.
Here's my list. I think they're pretty similar, but the two most notable differences are the manabase (I decided to follow darren's suit and stick with a traditional, non-budget manabase) as well as cutting almost all the Champion dorks as well as Myr Galvanizer - I drew the Galvanizer in about half the games I played and he was incredibly mediocre every time, I'm not convinced he's worth running just for the combo alone.
Looking ahead, in addition to Risen Reef, I'm probably going to pick up Wirewood Symbiote and give it a try too (though I worry about having too many bouncers and not enough things to do with the bounce). Coat of Arms is an idea I hadn't considered (though it seems so obvious that I'm not sure why) so I might try and test that. I'm also going to try and explore the idea of running a lot of tribal-exclusionary wraths as a way of keeping up on board to buy time for my synergies to come together - I'm already running Crux of Fate and Widespread Brutality, and Wakening Sun's Avatar was a recent inclusion I'm eager to try out, but Rakdos, the Showstopper might find its way back in and Hythonia the Cruel might work OK as well (though I'm more dubious of that one).
How has the deck been running for you. Could you post your list? I'm curious to know how similar it is to my own. Any particular standout cards? I've been running into a bunch of wrath spells and been getting blown out. Have you had this problem at all? This deck top-decks terribly and really wants to over-commit to the board for maximum value.
I've only played about 5 or 6 games so the sample size isn't large, but so far it's played about how I thought it would, I.E. with wild swings of variance. Of those games, the highest point was curving Manaweft Sliver + changelings into turn 4 Sliver Queen into turn 5 tutor for Hibernation Sliver which helped dodge a wrath that same turn cycle, turn 6 I replayed everything and then finally turn 7 I assembled Cloudshredder Sliver + Reaper King + Impostor of the Sixth Pride in play, which with the other two slivers is "Pay 2 life: Destroy target permanent". My opponents scooped to just that combo, and I even randomly drew into Tolsimir that turn but was a mana short of playing it alongside everything else. That's probably the closest thing to this deck's nut draw.
The lowest point was being stuck on 4 lands for most of another game, with a draw that had both Hibernation Sliver and Walker of Secret Ways but no ways to abuse them and only 1 changeling to go along with my various tribal lords. Ways to filter cards or hit land drops seem pretty important for making sure the deck can function into the late game. I wish I could play like 5 copies of Elder Pine of Jukai.
Two cards that seemed continuously impressive without ever being cast were Patriarch's Bidding and Living Death. Half the games I played I had one of these cards in hand and could play to the board knowing I could get everything back if a wrath hit (though I never actually cast them, either because I wasn't wrathed and won or because I died with my board in tact). Living Death being a pseudo-wrath that gets around indestructible is nice too.
I finally put my deck together and played some games, and so far it's been a blast. Strangely I kept drawing the same half of the deck (I cast Knowledge Exploitation on turn 4 three games in a row) so I'm looking forward to playing with Higure and some of the other cards that have been talked about.
Looking at cards from the new set ...
Kaalia, Zenith Seeker - A good, efficient flying body that has a decent chance of drawing 1 or 2 cards with the deck running 18+ changelings as well as some actual dragons, Kaalia might squeeze in for me. Might need some testing to see how reliable the draw is. If this ever draws 3 its insane.
Omnath, Locus of the Roil - I'm more unsure about this one. It'll be an FTK a reasonable amount of the time which is alright, and slowly growing our changelings or itself into bigger threats is nice (especially for me since I'm running the full suite of fetches), but we don't run enough land ramp to reliably get to 8 lands and that's where most of the value of this thing lies. I was initially high on it, but thinking about it more has me less optimistic.
Other than those and Risen Reef (which is an auto-include), I'm not seeing anything else worth running.
I still run Higure of the Still Wind. I wonder if this guy would be better. Waaay less awesome, but I might make that swap.
How has Higure been for you? I'm still getting the pieces of my deck together so I've had no experience, but it seems like you won't often get in multiple hits with multiple changelings at a time to make Ingenious Infiltrator good, whereas with Higure you only need 1 hit and then you can tutor your best changeling (or Yuriko) and then repeatedly make Higure or your changelings unblockable. I do like that Infiltrator is only 2 mana to Ninjutsu, that's twice as cheap as Higure, but it still seems like Higure would get more mileage in the long run. How important has Higure's unblockability been?
I look forward to countering some spells with a moggcatcher activation.
Unfortunately that doesn't work, as Unsettled Mariner needs to be in play when the casting/activation/triggering of the spell or ability happens for its ability to trigger.
We're pretty much on the same page for everything else. :>
Oh... I hadn't even thought about adding this guy. I'm too busy trying to figure out what I'm going to cut to add Hibernation Sliver. This one is super fantastic for sure... but I have way too many slivers. I'm going to pass on it.
For Hibernation Sliver, have you considered cutting Sliver Hivelord? HS and Hivelord both essentially do the same thing, protect your board from wraths and removal, but HS protects from all kinds of removal, not just destroy effects, admittedly at a loss of life and tempo, made up for slightly by its much cheaper casting cost. Plus cutting a sliver keeps your equilibrium of creature types in check.
Those 3 were also the first ones I landed on for cutting. I also decided to break up the O-Ring changeling loop by cutting 2 of the 3 Champion changelings, as the deck has better combos now and it feels like any hand where I have 2 or 3 of them at once would be a bit awkward. I think I'm gonna keep 1 in though just because having the ability to fetch one out with Skyshroud Poacher and friends to save an important creature from a wrath seems like a play I'd like to have available once in a game (not sure if I'll go with Changeling Hero for lifegain, considering how much I seem to be abusing Hibernation Sliver, or Changeling Titan just because he's gigantic).
Man, this set really added a lot to help this deck become more refined. I'm curious to hear your thoughts on some of the new cards. Here's all the ones I'm looking at:
Irregular Cohort - This one seems like a slam-dunk; two changeling bodies at a reasonably cheap 3 mana to double-trigger our Unesh and such while also providing multiple bodies to tap for mana. It also goes infinite a number of ways. Haste outlet + mana outlet + Walker of Secret Ways + Cryptic Gateway = infinite ETBs (EDIT: Nope nevermind, this is a nonbo, forgot that you're tapping the creatures for Gateway and thus can't also tap them for mana). The previously mentioned Hibernation Sliver + Tolsimir, Friend to Wolves synergy alongside Cryptic Gateway gets infinite life + ETBs AND infinite (tapped) tokens by responding to the Gateway activation by bouncing Cohort back with the Sliver's ability.
Valiant Changeling - This one I'm unsure how to evaluate. The new set added enough 1 mana changelings that this will sometimes be castable on turn 2 which is great, but without a changeling it's sketchy. The deck has enough creatures with two or more creature types that I think it'll be castable for 3-4 a reasonable amount of the time even when we don't have another changeling, but even then that's pretty bad, and lategame it seems likely to be bricked by larger creatures. It does have some neat synergies with Yuriko and Seshiro though. I'll probably try it but I think the deck actually has better options.
Changeling Outcast - Works amazingly with Yuriko and Seshiro and friends and costs 1. Definitely in.
Graveshifter - This is definitely worth including right? It's a bit awkward that there's going to be spots early game where we want to play a changeling for tribal synergies but don't have a creature in the yard, but being able to get back our strong tribal card lategame seems more than worth it.
Undead Augur - I'll just mention that maybe in a version of this deck that's more sacrifice heavy this would be a good include. As is it's probably too difficult to trigger reliably without sac outlets.
Ayula, Queen Among Bears - I think this card requires too much work to be good. Needing to play this out BEFORE playing changelings, and then needing to build up enough counters on one of our tiny changelings to be big enough to fight seems real bad. Maybe just because it's cheap and has a unique tribe that makes it appealing, but I'm unconvinced.
Webweaver Changeling - Seems wayyy too expensive. The lifegain is whatever, and being a big reach body is fine, but I don't want to spend 4 mana on a medium changeling.
Cloudshredder Sliver - Both flying AND haste are abilities this deck wants a lot and there's no other card that does both this efficiently, it's just unfortunate it's attached to a sliver (since I've taken your stance in trying to diversify creature types as much as possible). I think it's likely this makes it in for me though.
The First Sliver - I feel like there's some sort of silly combo this enables, but right now I'm not seeing it. As is, it's another Sliver that's expensive and is doing something the deck already does (draw cards/generate value) with a creature type we already run plenty of. Seems like an easy pass. I'd rather play Sliver Overlord.
Ingenious Infiltrator - We already have this effect a bunch as well, and we also have a bunch of Ninjas already. It's just a weaker Yuriko. Nah.
Unsettled Mariner - Seems like an easy include. No mana discount, but making other players pay a tax to mess with our stuff seems great.
Universal Automaton - Ohhhhh boy they did it. 0 mana changeling. Everything I said about Irregular Cohort applies to this guy except you can totally remove Cryptic Gateway from the equation (EDIT: and add in Training Grounds for the first combo I guess). There's gotta be something else that goes off with this guy, but I don't feel like diving into that now. Never thought I'd be this excited for a Memnite. EDIT: Hah, well if nothing else Hibernation Sliver + this + Reaper King is "Pay 2 life: Destroy target permanent", which is incredibly amusing.
Combined with the Ur-Dragon it’ll make a bunch of changelings cost 0 mana (like that new Imposter of the Sixth Pride). I’ll need to find some more infinite combos based around that I think.
Surprise surprise, Cloudstone Curio is a busted with yet another card. Keep bouncing 1 or 2 mana changelings to your hand and trigger your infinite lifegain off Tolsimir, vindicates from Reaper King, card draw off Unesh or Wirewood Savage, etc. Gilt-Leaf Archdruid draws infinite cards as well, and then once you have 7 changelings in hand you can play them all, then with the Curio trigger on the stack, steal someone's lands, resolve Curio to bounce back a changeling, then play it again to return your tapped changelings to hand then replay them again, effectively untapping them to steal the table's lands. Aluren offers a bit of redundancy to this combo as well (though TBH with threedirect-to-playtutors, it's probably egregious). Curio is also a good card by itself, since the deck has so many cheap 1-2 mana changelings (with more hopefully coming with MH) so it can juggle them to trigger Lathliss and Spit Flame and the like. With the tutor creatures you can also save your important creatures from wraths with Curio.
For a more tribal-based combo, Hibernation Sliver + Tolsimir, Friend to Wolves gets you infinite life and infinite ETBs with any cheap changeling. If you have a haste outlet and a mana-maker, it's also infinite mana. Hibernation Sliver also seems decent in the deck already for the same reasons Cloudstone Curio would be. There's also probably something you can do with Arcane Adaptation to break it, but right now I'm not seeing it.
You've got 33 creature types but none of them are Zombie?
Graveborn Muse seems like the best candidate to me, as a Phyrexian Arena on a body, except this Arena can easily draw you 5+ cards a turn if you flood the board with Changelings which compensates for the main weakness of Arena (drawing cards too slowly). If you're losing too much life, you can Champion it away, chump attack/block with it etc.
For less damaging card draw, Gisa and Geralf act like Wort, Boggart Auntie #2, with some minor downsides and upsides: they can't get back Crib Swap; they don't let you hoard changelings in your hand, you have to cast one every turn or lose value; you get to cast a changeling the turn you play them; they mill you to make it more likely to have stuff to cast; they've got a bigger body but no evasion. I'd try and fit both in if you can.
I'll also mention two other options though I think they're both weaker. Cryptbreaker does his best impression of Kumena, Tyrant of Orazca's good ability while also being way cheaper and providing additional bodies to block, attack, and tap for cards. Rooftop Storm is expensive and is pretty bad at casting your mostly cheap changelings, but combined with Artificial Evolution of Arcane Adaptation it can do some silly stuff.
I might end up building my own version of this deck in the future, hope you don't mind me stealing the idea. :>
TBF I never really played with the Champion dorks much; I goldfished the deck a couple times and they were consistently awkward and not very useful to cast so I cut them early on in testing. I did recently manage to protect a creature from a wrath (ironically a Crux of Fate) by tutoring up my one Champion dork to protect it, but that's a play I can't see making more than once in a game generally speaking. I'll pay attention to how often I want to tutor them up in the future. My other issue with Galvanizer, aside from half its use being with combo, is its other main use is generating lots of mana and cards with things like Manaweft Sliver or Azami, but generally speaking when I have one of those cards + a couple of changelings the deck is already performing extremely well, so it feels a bit win-more.
The meta I play this deck in generally has a lot of "fair" creature decks so it's important for me to have an answer to a scary board at some point or another. I only just put the Avatar in so no idea how it plays yet; half the reason I'm running it is just to check off Dinosaur. :>
For me Hivelord has been pretty great, granted the couples times I drew it I also had a mana dork to help activate it quickly. It also has some amazing tutor targets. Hibernation Sliver has been one of the best cards in the deck for me, protecting me from wraths, working well with ETBs, and of course being a combo piece. Harmonic Sliver has been key to stopping some shenanigans. I also run a slightly bigger Sliver package with Cloudshredder Sliver. Being a big 7/7 is also nice for holding off attacks or attacking itself. If your meta is faster it might be a reasonable cut though.
I played a game recently where another player at the table played Coat of Arms, and that was enough to convince me it probably doesn't belong in my deck. There's too many ways for other players to have more creature than me since the deck doesn't really make tokens, and me having 2 or 3 15/15s isn't as good as someone having 8 10/10s.
And I'll definitely be joining you there. :>
1x The Ur-Dragon
Land (36)
1x Mutavault
1x Swarmyard
1x Murmuring Bosk
1x Arid Mesa
1x Badlands
1x Bayou
1x Blood Crypt
1x Bloodstained Mire
1x Breeding Pool
1x Command Tower
1x Exotic Orchard
1x Flooded Strand
1x Godless Shrine
1x Hallowed Fountain
1x Marsh Flats
1x Misty Rainforest
1x Overgrown Tomb
1x Path of Ancestry
1x Plateau
1x Polluted Delta
1x Sacred Foundry
1x Savannah
1x Scalding Tarn
1x Scrubland
1x Steam Vents
1x Stomping Ground
1x Taiga
1x Temple Garden
1x Tropical Island
1x Tundra
1x Underground Sea
1x Verdant Catacombs
1x Volcanic Island
1x Watery Grave
1x Windswept Heath
1x Wooded Foothills
1x Amoeboid Changeling
1x Avian Changeling
1x Chameleon Colossus
1x Changeling Hero
1x Changeling Outcast
1x Fire-Belly Changeling
1x Graveshifter
1x Impostor of the Sixth Pride
1x Irregular Cohort
1x Mirror Entity
1x Moonglove Changeling
1x Morophon, the Boundless
1x Mothdust Changeling
1x Shapesharer
1x Skeletal Changeling
1x Taurean Mauler
1x Universal Automaton
1x Unsettled Mariner
1x Valiant Changeling
1x Venomous Changeling
1x Woodland Changeling
1x Crib Swap
Wizards
1x Azami, Lady of Scrolls
1x Sigil Tracer
Slivers
1x Cloudshredder Sliver
1x Gemhide Sliver
1x Harmonic Sliver
1x Hibernation Sliver
1x Manaweft Sliver
1x Sliver Overlord
Spirits
1x Elder Pine of Jukai
Druids
1x Gilt-Leaf Archdruid
Allys
1x Harabaz Druid
1x Sea Gate Loremaster
1x Tuktuk Scrapper
1x Higure, the Still Wind
1x Walker of Secret Ways
1x Yuriko, the Tiger's Shadow
Knights
1x Khorvath Brightflame
Dragons
1x Lathliss, Dragon Queen
1x Sylvia Brightspear
1x Crux of Fate
1x Dragon's Hoard
1x Spit Flame
Rebels
1x Lin Sivvi, Defiant Hero
Goblins
1x Moggcatcher
Elves
1x Priest of Titania
1x Skyshroud Poacher
Cats
1x Qasali Slingers
Scarecrows
1x Reaper King
Shamans
1x Sachi, Daughter of Seshiro
Merfolk
1x Seahunter
Snakes
1x Seshiro the Anointed
Wolves
1x Tolsimir, Friend to Wolves
Sphinxes
1x Unesh, Criosphinx Sovereign
Dinosaurs
1x Wakening Sun's Avatar
Beasts
1x Wirewood Savage
Demons
1x Liliana's Contract
Rogues
1x Knowledge Exploitation
Armys
1x Widespread Brutality
Tribal Support
1x Living Death
1x Patriarch's Bidding
1x Peer Pressure
Looking ahead, in addition to Risen Reef, I'm probably going to pick up Wirewood Symbiote and give it a try too (though I worry about having too many bouncers and not enough things to do with the bounce). Coat of Arms is an idea I hadn't considered (though it seems so obvious that I'm not sure why) so I might try and test that. I'm also going to try and explore the idea of running a lot of tribal-exclusionary wraths as a way of keeping up on board to buy time for my synergies to come together - I'm already running Crux of Fate and Widespread Brutality, and Wakening Sun's Avatar was a recent inclusion I'm eager to try out, but Rakdos, the Showstopper might find its way back in and Hythonia the Cruel might work OK as well (though I'm more dubious of that one).
I've only played about 5 or 6 games so the sample size isn't large, but so far it's played about how I thought it would, I.E. with wild swings of variance. Of those games, the highest point was curving Manaweft Sliver + changelings into turn 4 Sliver Queen into turn 5 tutor for Hibernation Sliver which helped dodge a wrath that same turn cycle, turn 6 I replayed everything and then finally turn 7 I assembled Cloudshredder Sliver + Reaper King + Impostor of the Sixth Pride in play, which with the other two slivers is "Pay 2 life: Destroy target permanent". My opponents scooped to just that combo, and I even randomly drew into Tolsimir that turn but was a mana short of playing it alongside everything else. That's probably the closest thing to this deck's nut draw.
The lowest point was being stuck on 4 lands for most of another game, with a draw that had both Hibernation Sliver and Walker of Secret Ways but no ways to abuse them and only 1 changeling to go along with my various tribal lords. Ways to filter cards or hit land drops seem pretty important for making sure the deck can function into the late game. I wish I could play like 5 copies of Elder Pine of Jukai.
Two cards that seemed continuously impressive without ever being cast were Patriarch's Bidding and Living Death. Half the games I played I had one of these cards in hand and could play to the board knowing I could get everything back if a wrath hit (though I never actually cast them, either because I wasn't wrathed and won or because I died with my board in tact). Living Death being a pseudo-wrath that gets around indestructible is nice too.
Looking at cards from the new set ...
Kaalia, Zenith Seeker - A good, efficient flying body that has a decent chance of drawing 1 or 2 cards with the deck running 18+ changelings as well as some actual dragons, Kaalia might squeeze in for me. Might need some testing to see how reliable the draw is. If this ever draws 3 its insane.
Omnath, Locus of the Roil - I'm more unsure about this one. It'll be an FTK a reasonable amount of the time which is alright, and slowly growing our changelings or itself into bigger threats is nice (especially for me since I'm running the full suite of fetches), but we don't run enough land ramp to reliably get to 8 lands and that's where most of the value of this thing lies. I was initially high on it, but thinking about it more has me less optimistic.
Other than those and Risen Reef (which is an auto-include), I'm not seeing anything else worth running.
How has Higure been for you? I'm still getting the pieces of my deck together so I've had no experience, but it seems like you won't often get in multiple hits with multiple changelings at a time to make Ingenious Infiltrator good, whereas with Higure you only need 1 hit and then you can tutor your best changeling (or Yuriko) and then repeatedly make Higure or your changelings unblockable. I do like that Infiltrator is only 2 mana to Ninjutsu, that's twice as cheap as Higure, but it still seems like Higure would get more mileage in the long run. How important has Higure's unblockability been?
Unfortunately that doesn't work, as Unsettled Mariner needs to be in play when the casting/activation/triggering of the spell or ability happens for its ability to trigger.
We're pretty much on the same page for everything else. :>
For Hibernation Sliver, have you considered cutting Sliver Hivelord? HS and Hivelord both essentially do the same thing, protect your board from wraths and removal, but HS protects from all kinds of removal, not just destroy effects, admittedly at a loss of life and tempo, made up for slightly by its much cheaper casting cost. Plus cutting a sliver keeps your equilibrium of creature types in check.
Those 3 were also the first ones I landed on for cutting. I also decided to break up the O-Ring changeling loop by cutting 2 of the 3 Champion changelings, as the deck has better combos now and it feels like any hand where I have 2 or 3 of them at once would be a bit awkward. I think I'm gonna keep 1 in though just because having the ability to fetch one out with Skyshroud Poacher and friends to save an important creature from a wrath seems like a play I'd like to have available once in a game (not sure if I'll go with Changeling Hero for lifegain, considering how much I seem to be abusing Hibernation Sliver, or Changeling Titan just because he's gigantic).
Irregular Cohort - This one seems like a slam-dunk; two changeling bodies at a reasonably cheap 3 mana to double-trigger our Unesh and such while also providing multiple bodies to tap for mana. It also goes infinite a number of ways.
Haste outlet + mana outlet + Walker of Secret Ways + Cryptic Gateway = infinite ETBs(EDIT: Nope nevermind, this is a nonbo, forgot that you're tapping the creatures for Gateway and thus can't also tap them for mana). The previously mentioned Hibernation Sliver + Tolsimir, Friend to Wolves synergy alongside Cryptic Gateway gets infinite life + ETBs AND infinite (tapped) tokens by responding to the Gateway activation by bouncing Cohort back with the Sliver's ability.Impostor of the Sixth Pride - 1 mana changelings are the best. I'll probably cut one of the more medium 4/3 mana options I was running like Ghostly Changeling.
Valiant Changeling - This one I'm unsure how to evaluate. The new set added enough 1 mana changelings that this will sometimes be castable on turn 2 which is great, but without a changeling it's sketchy. The deck has enough creatures with two or more creature types that I think it'll be castable for 3-4 a reasonable amount of the time even when we don't have another changeling, but even then that's pretty bad, and lategame it seems likely to be bricked by larger creatures. It does have some neat synergies with Yuriko and Seshiro though. I'll probably try it but I think the deck actually has better options.
Changeling Outcast - Works amazingly with Yuriko and Seshiro and friends and costs 1. Definitely in.
Graveshifter - This is definitely worth including right? It's a bit awkward that there's going to be spots early game where we want to play a changeling for tribal synergies but don't have a creature in the yard, but being able to get back our strong tribal card lategame seems more than worth it.
Undead Augur - I'll just mention that maybe in a version of this deck that's more sacrifice heavy this would be a good include. As is it's probably too difficult to trigger reliably without sac outlets.
Venomous Changeling - As mentioned, this card is great with a couple of cards in the deck like Widespread Brutality. Definitely makes it in.
Ayula, Queen Among Bears - I think this card requires too much work to be good. Needing to play this out BEFORE playing changelings, and then needing to build up enough counters on one of our tiny changelings to be big enough to fight seems real bad. Maybe just because it's cheap and has a unique tribe that makes it appealing, but I'm unconvinced.
Webweaver Changeling - Seems wayyy too expensive. The lifegain is whatever, and being a big reach body is fine, but I don't want to spend 4 mana on a medium changeling.
Cloudshredder Sliver - Both flying AND haste are abilities this deck wants a lot and there's no other card that does both this efficiently, it's just unfortunate it's attached to a sliver (since I've taken your stance in trying to diversify creature types as much as possible). I think it's likely this makes it in for me though.
The First Sliver - I feel like there's some sort of silly combo this enables, but right now I'm not seeing it. As is, it's another Sliver that's expensive and is doing something the deck already does (draw cards/generate value) with a creature type we already run plenty of. Seems like an easy pass. I'd rather play Sliver Overlord.
Ingenious Infiltrator - We already have this effect a bunch as well, and we also have a bunch of Ninjas already. It's just a weaker Yuriko. Nah.
Unsettled Mariner - Seems like an easy include. No mana discount, but making other players pay a tax to mess with our stuff seems great.
Morophon, the Boundless - He's definitely in.
Birthing Boughs - Wayyyy too much mana. No thanks.
Universal Automaton - Ohhhhh boy they did it. 0 mana changeling. Everything I said about Irregular Cohort applies to this guy except you can totally remove Cryptic Gateway from the equation (EDIT: and add in Training Grounds for the first combo I guess). There's gotta be something else that goes off with this guy, but I don't feel like diving into that now. Never thought I'd be this excited for a Memnite. EDIT: Hah, well if nothing else Hibernation Sliver + this + Reaper King is "Pay 2 life: Destroy target permanent", which is incredibly amusing.
Surprise surprise, Cloudstone Curio is a busted with yet another card. Keep bouncing 1 or 2 mana changelings to your hand and trigger your infinite lifegain off Tolsimir, vindicates from Reaper King, card draw off Unesh or Wirewood Savage, etc. Gilt-Leaf Archdruid draws infinite cards as well, and then once you have 7 changelings in hand you can play them all, then with the Curio trigger on the stack, steal someone's lands, resolve Curio to bounce back a changeling, then play it again to return your tapped changelings to hand then replay them again, effectively untapping them to steal the table's lands. Aluren offers a bit of redundancy to this combo as well (though TBH with three direct-to-play tutors, it's probably egregious). Curio is also a good card by itself, since the deck has so many cheap 1-2 mana changelings (with more hopefully coming with MH) so it can juggle them to trigger Lathliss and Spit Flame and the like. With the tutor creatures you can also save your important creatures from wraths with Curio.
For a more tribal-based combo, Hibernation Sliver + Tolsimir, Friend to Wolves gets you infinite life and infinite ETBs with any cheap changeling. If you have a haste outlet and a mana-maker, it's also infinite mana. Hibernation Sliver also seems decent in the deck already for the same reasons Cloudstone Curio would be. There's also probably something you can do with Arcane Adaptation to break it, but right now I'm not seeing it.
Welp, I've gotta start ordering the cards I need now. Making the Ur-Dragon cost 4 mana with a giant tutorable body is pretty slick.
Graveborn Muse seems like the best candidate to me, as a Phyrexian Arena on a body, except this Arena can easily draw you 5+ cards a turn if you flood the board with Changelings which compensates for the main weakness of Arena (drawing cards too slowly). If you're losing too much life, you can Champion it away, chump attack/block with it etc.
For less damaging card draw, Gisa and Geralf act like Wort, Boggart Auntie #2, with some minor downsides and upsides: they can't get back Crib Swap; they don't let you hoard changelings in your hand, you have to cast one every turn or lose value; you get to cast a changeling the turn you play them; they mill you to make it more likely to have stuff to cast; they've got a bigger body but no evasion. I'd try and fit both in if you can.
I'll also mention two other options though I think they're both weaker. Cryptbreaker does his best impression of Kumena, Tyrant of Orazca's good ability while also being way cheaper and providing additional bodies to block, attack, and tap for cards. Rooftop Storm is expensive and is pretty bad at casting your mostly cheap changelings, but combined with Artificial Evolution of Arcane Adaptation it can do some silly stuff.
I might end up building my own version of this deck in the future, hope you don't mind me stealing the idea. :>