Okaun, Eye of Chaos

Partner with Zndrsplt, Eye of Wisdom (When this creature enters, target player may put Zndrsplt into their hand from their library, then shuffle.)
At the beginning of combat on your turn, flip a coin until you lose a flip.
Whenever a player wins a coin flip, double Okaun's power and toughness until end of turn.

Stormchaser Chimera

Flying
{2}{U}{R}: Scry 1, then reveal the top card of your library. Stormchaser Chimera gets +X/+0 until end of turn, where X is that card's mana value. (To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Chaotic Goo

Chaotic Goo enters with three +1/+1 counters on it.
At the beginning of your upkeep, you may flip a coin. If you win the flip, put a +1/+1 counter on Chaotic Goo. If you lose the flip, remove a +1/+1 counter from Chaotic Goo.

Goblin Assassin

Whenever Goblin Assassin or another Goblin enters, each player flips a coin. Each player whose coin comes up tails sacrifices a creature of their choice.

Zndrsplt, Eye of Wisdom

Partner with Okaun, Eye of Chaos (When this creature enters, target player may put Okaun into their hand from their library, then shuffle.)
At the beginning of combat on your turn, flip a coin until you lose a flip.
Whenever a player wins a coin flip, draw a card.

Mindshrieker

Flying
{2}: Target player mills a card. Mindshrieker gets +X/+X until end of turn, where X is the milled card's mana value.

Orcish Captain

{1}: Flip a coin. If you win the flip, target Orc creature gets +2/+0 until end of turn. If you lose the flip, it gets -0/-2 until end of turn.

Charmbreaker Devils

At the beginning of your upkeep, return an instant or sorcery card at random from your graveyard to your hand.
Whenever you cast an instant or sorcery spell, Charmbreaker Devils gets +4/+0 until end of turn.

Capricious Efreet

At the beginning of your upkeep, choose target nonland permanent you control and up to two target nonland permanents you don't control. Destroy one of them at random.

Goblin Bangchuckers

{T}: Flip a coin. If you win the flip, Goblin Bangchuckers deals 2 damage to any target. If you lose the flip, Goblin Bangchuckers deals 2 damage to itself.

Karplusan Minotaur

Cumulative upkeep—Flip a coin. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever you win a coin flip, Karplusan Minotaur deals 1 damage to any target.
Whenever you lose a coin flip, Karplusan Minotaur deals 1 damage to any target of an opponent's choice.

Goblin Archaeologist

{R}, {T}: Flip a coin. If you win the flip, destroy target artifact and untap Goblin Archaeologist. If you lose the flip, sacrifice Goblin Archaeologist.

Tyrant of Discord

When Tyrant of Discord enters, target opponent chooses a permanent they control at random and sacrifices it. If a nonland permanent is sacrificed this way, repeat this process.

Goblin Kaboomist

At the beginning of your upkeep, create a colorless artifact token named Land Mine with "{R}, Sacrifice this artifact: This artifact deals 2 damage to target attacking creature without flying." Then flip a coin. If you lose the flip, Goblin Kaboomist deals 2 damage to itself.

Creepy Doll

Indestructible
Whenever Creepy Doll deals combat damage to a creature, flip a coin. If you win the flip, destroy that creature.

Crazed Firecat

When Crazed Firecat enters, flip a coin until you lose a flip. Put a +1/+1 counter on Crazed Firecat for each flip you won.

Marchesa's Smuggler

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
{1}{U}{R}: Target creature you control gains haste until end of turn and can't be blocked this turn.

Volatile Rig

Trample
Volatile Rig attacks each combat if able.
Whenever Volatile Rig is dealt damage, flip a coin. If you lose the flip, sacrifice Volatile Rig.
When Volatile Rig dies, flip a coin. If you lose the flip, it deals 4 damage to each creature and each player.