Frenetic Sliver

All Slivers have "{0}: If this permanent is on the battlefield, flip a coin. If you win the flip, exile this permanent and return it to the battlefield under its owner's control at the beginning of the next end step. If you lose the flip, sacrifice it."

Mogg Assassin

{T}: You choose target creature an opponent controls, and that opponent chooses target creature. Flip a coin. If you win the flip, destroy the creature you chose. If you lose the flip, destroy the creature your opponent chose.

Chance Encounter

Whenever you win a coin flip, put a luck counter on Chance Encounter.
At the beginning of your upkeep, if Chance Encounter has ten or more luck counters on it, you win the game.

Skittish Valesk

At the beginning of your upkeep, flip a coin. If you lose the flip, turn Skittish Valesk face down.
Morph {5}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

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.

Creepy Doll

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

Yusri, Fortune's Flame

Flying
Whenever Yusri, Fortune's Flame attacks, choose a number between 1 and 5. Flip that many coins. For each flip you win, draw a card. For each flip you lose, Yusri deals 2 damage to you. If you won five flips this way, you may cast spells from your hand this turn without paying their mana costs.

Goblin Traprunner

Whenever Goblin Traprunner attacks, flip three coins. For each flip you win, create a 1/1 red Goblin creature token that's tapped and attacking.

Chaotic Strike

Cast this spell only during combat after blockers are declared.
Flip a coin. If you win the flip, target creature gets +1/+1 until end of turn.
Draw a card.

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.

Winter Sky

Flip a coin. If you win the flip, Winter Sky deals 1 damage to each creature and each player. If you lose the flip, each player draws a card.

Bottle of Suleiman

{1}, Sacrifice Bottle of Suleiman: Flip a coin. If you win the flip, create a 5/5 colorless Djinn artifact creature token with flying. If you lose the flip, Bottle of Suleiman deals 5 damage to you.

Puppet's Verdict

Flip a coin. If you win the flip, destroy all creatures with power 2 or less. If you lose the flip, destroy all creatures with power 3 or greater.

Goblin Assassin

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

Goblin Lyre

Sacrifice Goblin Lyre: Flip a coin. If you win the flip, Goblin Lyre deals damage to target opponent or planeswalker equal to the number of creatures you control. If you lose the flip, Goblin Lyre deals damage to you equal to the number of creatures that opponent or that planeswalker's controller controls.

Crooked Scales

{4}, {T}: Flip a coin. If you win the flip, destroy target creature an opponent controls. If you lose the flip, destroy target creature you control unless you pay {3} and repeat this process.

Goblin Festival

{2}: Goblin Festival deals 1 damage to any target. Flip a coin. If you lose the flip, choose one of your opponents. That player gains control of Goblin Festival.

Molten Birth

Create two 1/1 red Elemental creature tokens, then flip a coin. If you win the flip, return Molten Birth to its owner's hand.

Krark's Thumb

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

Tavern Scoundrel

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

Ral Zarek

+1: Tap target permanent, then untap another target permanent.
−2: Ral Zarek deals 3 damage to any target.
−7: Flip five coins. Take an extra turn after this one for each coin that comes up heads.

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.

Goblin Psychopath

Whenever Goblin Psychopath attacks or blocks, flip a coin. If you lose the flip, the next time it would deal combat damage this turn, it deals that damage to you instead.

Skyclaw Thrash

Whenever Skyclaw Thrash attacks, flip a coin. If you win the flip, Skyclaw Thrash gets +1/+1 and gains flying until end of turn.

Viashino Sandswimmer

{R}: Flip a coin. If you win the flip, return Viashino Sandswimmer to its owner's hand. If you lose the flip, sacrifice Viashino Sandswimmer.

Planar Chaos

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

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.

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.

Goblin Kites

{R}: Target creature you control with toughness 2 or less gains flying until end of turn. Flip a coin at the beginning of the next end step. If you lose the flip, sacrifice that creature.

Molten Sentry

As Molten Sentry enters the battlefield, flip a coin. If the coin comes up heads, Molten Sentry enters the battlefield as a 5/2 creature with haste. If it comes up tails, Molten Sentry enters the battlefield as a 2/5 creature with defender.

Boompile

{T}: Flip a coin. If you win the flip, destroy all nonland permanents.

Sakashima of a Thousand Faces

You may have Sakashima of a Thousand Faces enter the battlefield as a copy of another creature you control, except it has Sakashima of a Thousand Faces's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Aleatory

Cast this spell only during combat after blockers are declared.
Flip a coin. If you win the flip, target creature gets +1/+1 until end of turn.
Draw a card at the beginning of the next turn's upkeep.

Fickle Efreet

Whenever Fickle Efreet attacks or blocks, flip a coin at end of combat. If you lose the flip, an opponent gains control of Fickle Efreet.

Fiery Gambit

Flip a coin until you lose a flip or choose to stop flipping. If you lose a flip, Fiery Gambit has no effect. If you win one or more flips, Fiery Gambit deals 3 damage to target creature. If you win two or more flips, Fiery Gambit deals 6 damage to each opponent. If you win three or more flips, draw nine cards and untap all lands you control.

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.

Okaun, Eye of Chaos

Partner with Zndrsplt, Eye of Wisdom (When this creature enters the battlefield, 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.

Scoria Wurm

At the beginning of your upkeep, flip a coin. If you lose the flip, return Scoria Wurm to its owner's hand.

Goblin Bomb

At the beginning of your upkeep, you may flip a coin. If you win the flip, put a fuse counter on Goblin Bomb. If you lose the flip, remove a fuse counter from Goblin Bomb.
Remove five fuse counters from Goblin Bomb and sacrifice it: It deals 20 damage to target player or planeswalker.

Crazed Firecat

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

Two-Headed Giant

Whenever Two-Headed Giant attacks, flip two coins. If both coins come up heads, Two-Headed Giant gains double strike until end of turn. If both coins come up tails, Two-Headed Giant gains menace until end of turn.

Fighting Chance

For each blocking creature, flip a coin. If you win the flip, prevent all combat damage that would be dealt by that creature this turn.

Chaotic Goo

Chaotic Goo enters the battlefield 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 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.

Sorcerer's Strongbox

{2}, {T}: Flip a coin. If you win the flip, sacrifice Sorcerer's Strongbox and draw three cards.

Wirefly Hive

{3}, {T}: Flip a coin. If you win the flip, create a 2/2 colorless Insect artifact creature token with flying named Wirefly. If you lose the flip, destroy all permanents named Wirefly.

Risky Move

At the beginning of each player's upkeep, that player gains control of Risky Move.
When you gain control of Risky Move 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.

Frenetic Efreet

Flying
{0}: Flip a coin. If you win the flip, Frenetic Efreet phases out. If you lose the flip, sacrifice Frenetic Efreet. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)

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.

Krark, the Thumbless

Whenever you cast an instant or sorcery spell, flip a coin. If you lose the flip, return that spell to its owner's hand. If you win the flip, copy that spell, and you may choose new targets for the copy.
Partner (You can have two commanders if both have partner.)

Mijae Djinn

Whenever Mijae Djinn attacks, flip a coin. If you lose the flip, remove Mijae Djinn from combat and tap it.

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.

Mirror March

Whenever a nontoken creature enters the battlefield under your control, 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.

Tide of War

Whenever one or more creatures block, flip a coin. If you win the flip, each blocking creature is sacrificed by its controller. If you lose the flip, each blocked creature is sacrificed by its controller.

Goblin Artisans

{T}: Flip a coin. If you win the flip, draw a card. If you lose the flip, counter target artifact spell you control that isn't the target of an ability from another creature named Goblin Artisans.

Zndrsplt, Eye of Wisdom

Partner with Okaun, Eye of Chaos (When this creature enters the battlefield, 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.

Desperate Gambit

Choose a source you control and flip a coin. If you win the flip, the next time that source would deal damage this turn, it deals double that damage instead. If you lose the flip, the next time it would deal damage this turn, prevent that damage.

Stitch in Time

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

Mana Clash

You and target opponent each flip a coin. Mana Clash deals 1 damage to each player whose coin comes up tails. Repeat this process until both players' coins come up heads on the same flip.

Mutalith Vortex Beast

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