Pretty typical Kazuul build except that I decided to add some big ol' LD to ensure that his ability is always relevant, even for voltrons and the like, at any point in the game.
Deck ended up being ok but pretty weak to large evasive creatures that could just kill me without paying. Also people hated playing against it. Anyway still kind of an interesting idea. Damage doublers ended up being pretty risky, and maybe because I was playing against a lifegain deck but mana barbs also seemed pretty risky. Not really my kind of cards, but they seemed worth trying in this context.
Here are some cards you can consider. Maybe they can help with some areas you feel you need more "umph"
Vandalblast - Great artifact removal. Shattering Spree - More great artifact removal. Varchild's War-Riders - You seem ok with giving your opponent creatures. This one gives them 1/1s en masse Red Elemental Blast - There is always a blue player at the table. Blasphemous Act - You mentioned bigger creatures. Maybe this can help? Aftershock - This can single-target destory a creature, which you said can cause issues, but can also go after a land or artifact. Wake of Destruction - Because you probably still have too many friends left after playing your deck, you need to lose more, lol. Mana Geyser - Even if you bust lands, when your opponents have just 3 or 4 each and they are tapped, this cam give you quite a bit of mana.
Vandalblast and varchild's I would definitely include if I revised the decklist. shattering spree probably. The rest I'm less sure about. Blasty act I'm a bit nervous about since I don't really want to destroy ALL creatures, just large evasive ones.
Deck ended up being ok but pretty weak to large evasive creatures that could just kill me without paying. Also people hated playing against it. Anyway still kind of an interesting idea. Damage doublers ended up being pretty risky, and maybe because I was playing against a lifegain deck but mana barbs also seemed pretty risky. Not really my kind of cards, but they seemed worth trying in this context.
1 Kazuul, Tyrant of the Cliffs
Ramp (22)
1 Coldsteel Heart
1 Commander's Sphere
1 Fellwar Stone
1 Fire Diamond
1 Ruby Medallion
1 Mana Crypt
1 Sol Ring
1 Guantlet of Might
1 Hedron Archive
1 Magnifying Glass
1 Everflowing Chalice
1 Worn Powerstone
1 Unstable Obelisk
1 Mind Stone
1 Prismatic Lens
1 Thran Dynamo
1 Mana Vault
1 Thought Vessel
1 Astral Cornucopia
1 Koth of the Hammer
1 Chandra, Torch of Defiance
1 Spectral Searchlight
Removal (5)
1 Chaos Warp
1 Volcanic Offering
1 Karn Liberated
1 Ugin the Spirit Dragon
1 Erratic Portal
1 Warmonger Hellkite
1 Urabrask the Hidden
1 Rite of the Raging Storm
1 Avatar of Slaughter
1 Grenzo, Havoc Raiser
1 Rage Nimbus
1 Goblin Diplomats
1 Fumiko the Lowblood
1 Grand Melee
1 Hunted Dragon
1 Akroan Horse
1 Goblin Spymaster
Land Destruction (13)
1 Bend or Break
1 Epicenter
1 Burning Earth
1 Decree of Annihilation
1 Keldon Firebombers
1 Ruination
1 Winter Orb
1 Boom // Bust
1 Tectonic Break
1 Thoughts of Ruin
1 Impending Disaster
1 Devastating Dreams
1 Manabarbs
Let's Speed Things Up a Bit (6)
1 Rage Reflection
1 Dictate of the Twin Gods
1 Vicious Shadows
1 Gratuitous Violence
1 Warstorm Surge
1 Furnace of Rath
1 Forcefield
1 Maze of Ith
1 Thaumatic Compass
1 Glacial Crevasses
1 Sunstone
Other (2)
1 Gamble
1 Crucible of Worlds
Lands (34)
1 Drownyard Temple
1 Throne of the High City
1 Sandstone Needle
1 Sea Gate Wreckage
1 Ancient Tomb
1 Mystifying Maze
1 Darksteel Citadel
1 Forbidden Orchard
1 Wooded Foothills
1 Bloodstained Mire
1 Scalding Tarn
1 Arid Mesa
1 Scrying Sheets
21 snow-covered mountain
EDH Primers
Phelddagrif - Zirilan
EDH
Thrasios+Bruse - Pang - Sasaya - Wydwen - Feather - Rona - Toshiro - Sylvia+Khorvath - Geth - QMarchesa - Firesong - Athreos - Arixmethes - Isperia - Etali - Silas+Sidar - Saskia - Virtus+Gorm - Kynaios - Naban - Aryel - Mizzix - Kazuul - Tymna+Kraum - Sidar+Tymna - Ayli - Gwendlyn - Phelddagrif 4 - Liliana - Kaervek - Phelddagrif 3 - Mairsil - Scarab - Child - Phenax - Shirei - Thada - Depala - Circu - Kytheon - GrenzoHR - Phelddagrif - Reyhan+Kraum - Toshiro - Varolz - Nin - Ojutai - Tasigur - Zedruu - Uril - Edric - Wort - Zurgo - Nahiri - Grenzo - Kozilek - Yisan - Ink-Treader - Yisan - Brago - Sidisi - Toshiro - Alexi - Sygg - Brimaz - Sek'Kuar - Marchesa - Vish Kal - Iroas - Phelddagrif - Ephara - Derevi - Glissa - Wanderer - Saffi - Melek - Xiahou Dun - Lazav - Lin Sivvi - Zirilan - Glissa
PDH - Drake - Graverobber - Izzet GM - Tallowisp - Symbiote Brawl - Feather - Ugin - Jace - Scarab - Angrath - Vraska - Kumena Oathbreaker - Wrenn&6
Vandalblast - Great artifact removal.
Shattering Spree - More great artifact removal.
Varchild's War-Riders - You seem ok with giving your opponent creatures. This one gives them 1/1s en masse
Red Elemental Blast - There is always a blue player at the table.
Blasphemous Act - You mentioned bigger creatures. Maybe this can help?
Aftershock - This can single-target destory a creature, which you said can cause issues, but can also go after a land or artifact.
Wake of Destruction - Because you probably still have too many friends left after playing your deck, you need to lose more, lol.
Mana Geyser - Even if you bust lands, when your opponents have just 3 or 4 each and they are tapped, this cam give you quite a bit of mana.
Everything combos with Tombstone Stairwell.
EDH Primers
Phelddagrif - Zirilan
EDH
Thrasios+Bruse - Pang - Sasaya - Wydwen - Feather - Rona - Toshiro - Sylvia+Khorvath - Geth - QMarchesa - Firesong - Athreos - Arixmethes - Isperia - Etali - Silas+Sidar - Saskia - Virtus+Gorm - Kynaios - Naban - Aryel - Mizzix - Kazuul - Tymna+Kraum - Sidar+Tymna - Ayli - Gwendlyn - Phelddagrif 4 - Liliana - Kaervek - Phelddagrif 3 - Mairsil - Scarab - Child - Phenax - Shirei - Thada - Depala - Circu - Kytheon - GrenzoHR - Phelddagrif - Reyhan+Kraum - Toshiro - Varolz - Nin - Ojutai - Tasigur - Zedruu - Uril - Edric - Wort - Zurgo - Nahiri - Grenzo - Kozilek - Yisan - Ink-Treader - Yisan - Brago - Sidisi - Toshiro - Alexi - Sygg - Brimaz - Sek'Kuar - Marchesa - Vish Kal - Iroas - Phelddagrif - Ephara - Derevi - Glissa - Wanderer - Saffi - Melek - Xiahou Dun - Lazav - Lin Sivvi - Zirilan - Glissa
PDH - Drake - Graverobber - Izzet GM - Tallowisp - Symbiote Brawl - Feather - Ugin - Jace - Scarab - Angrath - Vraska - Kumena Oathbreaker - Wrenn&6