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.)

Restless Spire

This land enters tapped.
{T}: Add {U} or {R}.
{U}{R}: Until end of turn, this land becomes a 2/1 blue and red Elemental creature with "During your turn, this creature has first strike." It's still a land.
Whenever this land attacks, scry 1.

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."

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.

Sorcerer's Strongbox

{2}, {T}: Flip a coin. If you win the flip, sacrifice this artifact and draw three cards.

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.

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.

Goblin Assassin

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

Skittish Valesk

At the beginning of your upkeep, flip a coin. If you lose the flip, turn this creature 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.)

Yusri, Fortune's Flame

Flying
Whenever Yusri 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 Archaeologist

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

Goblin Bangchuckers

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

Scoria Wurm

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

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. This artifact deals 1 damage to you.

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.

Goblin Kaboomist

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

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.

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Chariot of Victory

Equipped creature has first strike, trample, and haste.
Equip {1}

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Bottle of Suleiman

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

Volatile Rig

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

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.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Goblin Psychopath

Whenever this creature 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.

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

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.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Chance Encounter

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

Stitch in Time

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

Krark's Thumb

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

Viashino Sandswimmer

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

Island

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

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.

Frostboil Snarl

As this land enters, you may reveal an Island or Mountain card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {R}.

Mijae Djinn

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

Sol Ring

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

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.

Molten Sentry

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

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

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.

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.

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.

Skyclaw Thrash

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

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.

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.

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.

Izzet Signet

Chaotic Goo

This creature 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 this creature. If you lose the flip, remove a +1/+1 counter from this creature.

Goblin Festival

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

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.

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.

Plasma Caster

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you get {E}{E} (two energy counters).
Pay {E}{E}: Choose target creature that's blocking equipped creature. Flip a coin. If you win the flip, exile the chosen creature. Otherwise, this Equipment deals 1 damage to it.
Equip {2}

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.

Crazed Firecat

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

Prismari Campus

This land enters tapped.
{T}: Add {U} or {R}.
{4}, {T}: Scry 1.

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 Morningstar

Equipped creature gets +1/+0 and has trample.
Equip {1}{R}
When this Equipment enters, roll a d20.
1—9 | Create a 1/1 red Goblin creature token.
10—20 | Create a 1/1 red Goblin creature token, then attach this Equipment to it.

Creepy Doll

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

Two-Headed Giant

Whenever this creature attacks, flip two coins. If both coins come up heads, this creature gains double strike until end of turn. If both coins come up tails, this creature gains menace until end of turn.

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.

Breeches, the Blastmaker

Menace
Whenever you cast your second spell each turn, you may sacrifice an artifact. If you do, flip a coin. When you win the flip, copy that spell. You may choose new targets for the copy. When you lose the flip, Breeches deals damage equal to that spell's mana value to any target.

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.

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.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Wild Wurm

When this creature enters, flip a coin. If you lose the flip, return this creature to its owner's hand.

Arcane Signet

Volatile Fjord

({T}: Add {U} or {R}.)
This land enters tapped.

Izzet Boilerworks

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Molten Tributary

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.

Goblin Traprunner

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

Mountain

Goblin Lyre

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

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.