Game of Chaos

Flip a coin. If you win the flip, you gain 1 life and target opponent loses 1 life, and you decide whether to flip again. If you lose the flip, you lose 1 life and that opponent gains 1 life, and that player decides whether to flip again. Double the life stakes with each flip.

Impulsive Maneuvers

Whenever a creature attacks, flip a coin. If you win the flip, the next time that creature would deal combat damage this turn, it deals double that damage instead. If you lose the flip, the next time that creature would deal combat damage this turn, prevent that damage.

Stitch in Time

Flip a coin. If you win the flip, take an extra turn after this one.

Skrelv, Defector Mite

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Skrelv can't block.
{W/P}, {T}: Choose a color. Another target creature you control gains toxic 1 and hexproof from that color until end of turn. It can't be blocked by creatures of that color this turn. ({W/P} can be paid with either {W} or 2 life.)

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.

Risky Move

At the beginning of each player's upkeep, that player gains control of this enchantment.
When you gain control of this enchantment from another player, choose a creature you control and an opponent. Flip a coin. If you lose the flip, that opponent gains control of that creature.

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru.
Partner (You can have two commanders if both have partner.)

Isamaru, Hound of Konda

Hope of Ghirapur

Flying
Sacrifice Hope of Ghirapur: Until your next turn, target player who was dealt combat damage by Hope of Ghirapur this turn can't cast noncreature spells.

Mutalith Vortex Beast

Trample
Warp Vortex — When this creature enters, flip a coin for each opponent you have. For each flip you win, draw a card. For each flip you lose, this creature deals 3 damage to that player.

Gideon, Battle-Forged

+2: Up to one target creature an opponent controls attacks Gideon during its controller's next turn if able.
+1: Until your next turn, target creature gains indestructible. Untap that creature.
0: Until end of turn, Gideon becomes a 4/4 Human Soldier creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.

Kytheon, Hero of Akros

At end of combat, if Kytheon and at least two other creatures attacked this combat, exile Kytheon, then return him to the battlefield transformed under his owner's control.
{2}{W}: Kytheon gains indestructible until end of turn.

Kytheon, Hero of Akros // Gideon, Battle-Forged

Zabaz, the Glimmerwasp

Modular 1
If a modular triggered ability would put one or more +1/+1 counters on a creature you control, that many plus one +1/+1 counters are put on it instead.
{R}: Destroy target artifact you control.
{W}: Zabaz gains flying until end of turn.

Tavern Scoundrel

Whenever you win a coin flip, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")
{1}, {T}, Sacrifice another permanent: Flip a coin.

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.

Norin, Swift Survivalist

Norin can't block.
Whenever a creature you control becomes blocked, you may exile it. You may play that card from exile this turn.

Kenzo the Hardhearted

Double strike; bushido 2 (Whenever this creature blocks or becomes blocked, it gets +2/+2 until end of turn.)

Bushi Tenderfoot

When a creature dealt damage by this creature this turn dies, flip this creature.

Bushi Tenderfoot // Kenzo the Hardhearted

Planar Chaos

At the beginning of your upkeep, flip a coin. If you lose the flip, sacrifice this enchantment.
Whenever a player casts a spell, that player flips a coin. If they lose the flip, counter that spell.

Krark's Thumb

If you would flip a coin, instead flip two coins and ignore one.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
{T}: Add {C}{C}.

Squee's Revenge

Choose a number. Flip a coin that many times or until you lose a flip, whichever comes first. If you win all the flips, draw two cards for each flip.

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

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, this creature deals 1 damage to any target.
Whenever you lose a coin flip, this creature deals 1 damage to any target of an opponent's choice.

Ragavan, Nimble Pilferer

Whenever Ragavan deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)