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.

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.

Island

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Creepy Doll

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

Cleansing Wildfire

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Draw a card.

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.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Opportunity

Winds of Change

Each player shuffles the cards from their hand into their library, then draws that many cards.

Chromatic Sphere

{1}, {T}, Sacrifice Chromatic Sphere: Add one mana of any color. Draw a card.

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

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 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.

Mountain

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.

Behold the Multiverse

Scry 2, then draw two cards.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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.

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.

Unexpected Windfall

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.

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.

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.

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.

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.

Mijae Djinn

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

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.

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.

Words of Wisdom

You draw two cards, then each other player draws a card.

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.

Enter the Infinite

Draw cards equal to the number of cards in your library, then put a card from your hand on top of your library. You have no maximum hand size until your next turn.

Ydwen Efreet

Whenever Ydwen Efreet blocks, flip a coin. If you lose the flip, remove Ydwen Efreet from combat and it can't block this turn. Creatures it was blocking that had become blocked by only Ydwen Efreet this combat become unblocked.

Mutalith Vortex Beast

Trample
Warp Vortex — When Mutalith Vortex Beast enters, 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.

Arcane Encyclopedia

Molten Sentry

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

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.

Tower of Fortunes

Dreamstone Hedron

{T}: Add {C}{C}{C}.
{3}, {T}, Sacrifice Dreamstone Hedron: Draw three cards.

Boompile

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

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, the Blastmaker deals damage equal to that spell's mana value to any target.

Blast of Genius

Choose any target. Draw three cards, then discard a card. Blast of Genius deals damage equal to the discarded card's mana value to that permanent or player.

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.

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

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.

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.

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.

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

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.

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.

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.)

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.

Stitch in Time

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

Sorcerer's Strongbox

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

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

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.

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.

Ancestral Reminiscence

Temple Bell

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.

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.

Magmatic Insight

As an additional cost to cast this spell, discard a land card.
Draw two cards.

Bonder's Ornament

{T}: Add one mana of any color.
{4}, {T}: Each player who controls a permanent named Bonder's Ornament draws a card.

Chromatic Star

{1}, {T}, Sacrifice Chromatic Star: Add one mana of any color.
When Chromatic Star is put into a graveyard from the battlefield, draw a card.

Scoria Wurm

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

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.)

Ghirapur Orrery

Each player may play an additional land on each of their turns.
At the beginning of each player's upkeep, if that player has no cards in hand, that player draws three cards.

Arcane Signet

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

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.

Divination

Krark's Thumb

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

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.

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.

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.

Sol Ring

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.

Concentrate

Horn of Greed

Whenever a player plays a land, that player draws a card.

Betrayal

Enchant creature an opponent controls
Whenever enchanted creature becomes tapped, you draw a card.