Dudename, Noun of the Red Verb - 2R
Legendary Creature - Elemental
Red mana doesn't empty from your mana pool.
When ~ leaves play, ~ deals x damage divided between any number of target creatures and players where x is the amount of red mana in your mana pool.
3/1
I like the guerrilla but I think I'd like it a whole lot more without the blue to be honest. The red white overlay makes it fall more into into a believable enough cunning tactician. Adding blue just makes it into yet another tricksy blue card being all tricksy and blue.
Champion's also nice but I think you could get away with him being a 5cc 4/4 or a 6cc 5/5 if you felt so inclined.
I'd go the chant/silence route myself to soft lock the opponent out of the game while you beat their faces in. Seems like it'd get you more mileage then just chucking burn.
Black seems like the preferable splash here. It has better sack engines in bloodthrone and seer and probably the best creature in standard to repeatedly chuck to sack effects in bloodghast.
Meldrik runs into Sea Drake territory. There's no down side if the requirements of his nominal drawback aren't met and its pretty damn easy to make sure they never will be. Just play him solo or with any other critter and start beating face at a laughably efficient pace.
Tomb Plunder 1B
Instant
Name a card. Exile cards from the top of your library until you exile the named card. Any opponent may have you put the named card into your hand. If they don't lose one life for all other cards exiled by ~ and put each of these cards into your hand.
Futile Wish 1B
Sorcery
Put a card you own from outside the game into your graveyard.
Wyrdbind UU
Enchantment
Flash
When ~ enters the battlefield exile target spell.
When ~ leaves the battlefield the exiled spell's owner may play it without paying its mana cost.
How about throwing (Alternate mana costs may still be paid. Additional costs that are not mana costs must still be paid) on for reminder text?
I don't think the wording as it stands would actually stop x spells. Admittedly my understanding of the niceties of the rules is a bit fast and loose but x as a variable is set at the time of casting, as far as the card's concerned the cost is unmodified and its being paid so its all kosher. You can still nuke someone with a fireball you just can't make ghithu fire instant or buyback a fan the flames.
I like the idea of making it splashable to but it seemed kind of broken at 2W and rule setting on that scale is kind of unequivocally white. The intent of the second clause is to stop abilities like affinity or delve from circumventing the first. As worded it only affects mana costs, so I don't see how it affects tertiary costs ala fling and its ilk. X spells sort slipped my mind at the time admittedly.
Dudename, Noun of the Red Verb - 2R
Legendary Creature - Elemental
Red mana doesn't empty from your mana pool.
When ~ leaves play, ~ deals x damage divided between any number of target creatures and players where x is the amount of red mana in your mana pool.
3/1
Champion's also nice but I think you could get away with him being a 5cc 4/4 or a 6cc 5/5 if you felt so inclined.
Instant
Name a card. Exile cards from the top of your library until you exile the named card. Any opponent may have you put the named card into your hand. If they don't lose one life for all other cards exiled by ~ and put each of these cards into your hand.
Futile Wish 1B
Sorcery
Put a card you own from outside the game into your graveyard.
Wyrdbind UU
Enchantment
Flash
When ~ enters the battlefield exile target spell.
When ~ leaves the battlefield the exiled spell's owner may play it without paying its mana cost.
I don't think the wording as it stands would actually stop x spells. Admittedly my understanding of the niceties of the rules is a bit fast and loose but x as a variable is set at the time of casting, as far as the card's concerned the cost is unmodified and its being paid so its all kosher. You can still nuke someone with a fireball you just can't make ghithu fire instant or buyback a fan the flames.
Enchantment
Players can't play spells without paying their mana costs.
Mana costs can't be modified.
Predatory Spark RR
Sorcery
~ deals 2 damage to target creature or player.
While you're searching your library, you may cast ~ from your library.
Mersae, Apothecary Adept 1W
Legendary Creature - Human Cleric
2: Regenerate target creature.
GW: Target creature gains death touch and/or lifelink until end of turn.
1/2
Off the top of my head I honestly can't name any blue cards that trigger positively off of land drops prior to zendikar.
Edit: Well there is trade routes, but that's kind of a stretch.