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.

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.

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.

Island

Krark's Thumb

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

Arid Mesa

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

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 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.

Tribute Mage

When this creature enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Reliquary Tower

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

Stormcarved Coast

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Shivan Reef

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

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Stitch in Time

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

Prismatic Vista

{T}, Pay 1 life, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield, then shuffle.

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 this enchantment.
At the beginning of your upkeep, if this enchantment has ten or more luck counters on it, you win the game.

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.)

Wooded Foothills

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Lavaglide Pathway

Riverglide Pathway

Riverglide Pathway // Lavaglide Pathway

The Gold Saucer

{T}: Add {C}.
{2}, {T}: Flip a coin. If you win the flip, create a Treasure token.
{3}, {T}, Sacrifice two artifacts: Draw a card.

Thundering Falls

({T}: Add {U} or {R}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

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.

Edgar, King of Figaro

When Edgar enters, draw a card for each artifact you control.
Two-Headed Coin — The first time you flip one or more coins each turn, those coins come up heads and you win those flips.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

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.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

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.

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Training Center

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Riverpyre Verge

{T}: Add {R}.
{T}: Add {U}. Activate only if you control an Island or a Mountain.

Command Tower

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

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.

Counterspell

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.

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.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

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.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Mountain

Invert Polarity

Choose target spell, then flip a coin. If you win the flip, gain control of that spell and you may choose new targets for it. If you lose the flip, counter that spell.

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.