Prowler's Helm

Equipped creature can't be blocked except by Walls.
Equip {2}

Krark's Thumb

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

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.

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Reliquary Tower

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

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with this enchantment on the bottom of their library in a random order.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Disallow

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

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.

Unwind

Counter target noncreature spell. Untap up to three lands.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

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.

Aether Tunnel

Enchant creature
Enchanted creature gets +1/+0 and can't be blocked.

Anger

Haste
As long as this card is in your graveyard and you control a Mountain, creatures you control have haste.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.

Aetherize

Return all attacking creatures to their owner's hand.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Ancient Silver Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Negate

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Decanter of Endless Water

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

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

Rogue's Passage

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

Barbarian Class

(Gain the next level as a sorcery to add its ability.)
If you would roll one or more dice, instead roll that many dice plus one and ignore the lowest roll.
{1}{R}: Level 2
Whenever you roll one or more dice, target creature you control gets +2/+0 and gains menace until end of turn.
{2}{R}: Level 3
Creatures you control have haste.

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.

Island

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Mana Leak

Counter target spell unless its controller pays {3}.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

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.

Volcanic Island

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.

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Counterspell

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Ancient Copper Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Chaos Dragon

Flying, haste
This creature attacks each combat if able.
At the beginning of combat on your turn, each player rolls a d20. If one or more opponents had the highest result, this creature can't attack those players or planeswalkers they control this combat.

Mountain

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.

Miscast

Counter target instant or sorcery spell unless its controller pays {3}.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Hoarding Ogre

Whenever this creature attacks, roll a d20.
1—9 | Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
10—19 | Create two Treasure tokens.
20 | Create three Treasure tokens.

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

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.

Delina, Wild Mage

Whenever Delina attacks, choose target creature you control, then roll a d20.
1—14 | Create a tapped and attacking token that's a copy of that creature, except it's not legendary and it has "At end of combat, exile this token."
15—20 | Create one of those tokens. You may roll again.

Feywild Trickster

Whenever you roll one or more dice, create a 1/1 blue Faerie Dragon creature token with flying.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Mental Misstep

({U/P} can be paid with either {U} or 2 life.)
Counter target spell with mana value 1.

Suspicious Bookcase

Defender
{3}, {T}: Target creature can't be blocked this 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.

Sol Ring

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Arcane Signet

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

Thought Vessel

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.

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.

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.

Dispel

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Scoria Wurm

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

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.