Whenever you attack, up to one target attacking creature can't be blocked this turn. Return that creature to its owner's hand at the beginning of the next end step. Choose a Background (You can have a Background as a second commander.)

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

You may have Imposter Mech enter the battlefield as a copy of a creature an opponent controls, except it's a Vehicle artifact with crew 3 and it loses all other card types. Crew 3

{T}: Add {C}. {T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

You may have Machine God's Effigy enter the battlefield as a copy of any creature on the battlefield, except it's an artifact and it has "{T}: Add {U}." (It's not a creature.) {T}: Add {U}.

{T}: Add {U}. {2}{U}: Put an hour counter on Midnight Clock. At the beginning of each upkeep, put an hour counter on Midnight Clock. When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Imprint — Whenever a nontoken creature dies, you may exile that card. If you do, return each other card exiled with Mimic Vat to its owner's graveyard. {3}, {T}: Create a token that's a copy of a card exiled with Mimic Vat. It gains haste. Exile it at the beginning of the next end step.

{T}: Add {C}. {1}, {T}, Sacrifice Mind Stone: Draw a card.

{2}: Mirage Mirror becomes a copy of target artifact, creature, enchantment, or land until end of turn.

The "legend rule" doesn't apply to permanents you control. Each legendary creature you control gets +1/+1. Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.) Equip {1}

You may have Auton Soldier enter the battlefield as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (Whenever it attacks, for each opponent other than defending player, you may put a token that's a copy of this creature onto the battlefield tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

You may have Body Double enter the battlefield as a copy of any creature card in a graveyard.

You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.

You may have Clone enter the battlefield as a copy of any creature on the battlefield.

Flying As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay. Whenever you cast a blue permanent spell, draw a card.

Genestealer's Kiss — Whenever Genestealer Patriarch attacks, put an infection counter on target creature defending player controls. Children of the Cult — Whenever a creature with an infection counter on it dies, you create a token that's a copy of that creature, except it's a Tyranid in addition to its other types.

You may have Gigantoplasm enter the battlefield as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."

Prototype {2}{U}{U} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) You may have Hulking Metamorph enter the battlefield as a copy of an artifact or creature you control, except it's an artifact creature in addition to its other types, and its power and toughness are equal to Hulking Metamorph's power and toughness.

Whenever Identity Thief attacks, you may exile another target nontoken creature. If you do, Identity Thief becomes a copy of that creature until end of turn. Return the exiled card to the battlefield under its owner's control at the beginning of the next end step.

Flying Lieutenant — At the beginning of combat on your turn, if you control your commander, draw a card.

Flash Flying You may have Malleable Impostor enter the battlefield as a copy of a creature an opponent controls, except it's a Faerie Shapeshifter in addition to its other types and it has flying.

You may have Mirror Image enter the battlefield as a copy of a creature you control.

Flash You may have Mocking Doppelganger enter the battlefield as a copy of a creature an opponent controls, except it has "Other creatures with the same name as this creature are goaded." (They attack each combat if able and attack a player other than you if able.)

Whenever Nascent Metamorph attacks or blocks, target opponent reveals cards from the top of their library until they reveal a creature card. Nascent Metamorph becomes a copy of that card until end of turn. Then that player puts all cards revealed this way on the bottom of their library in a random order.

Flying {T}: Add one mana of any color.

Flash When Phantom Steed enters the battlefield, exile another target creature you control until Phantom Steed leaves the battlefield. Whenever Phantom Steed attacks, create a tapped and attacking token that's a copy of the exiled card, except it's an Illusion in addition to its other types. Sacrifice that token at end of combat.

({U/P} can be paid with either {U} or 2 life.) You may have Phyrexian Metamorph enter the battlefield as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

When Solemn Simulacrum enters the battlefield, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. When Solemn Simulacrum dies, you may draw a card.

You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Flash You may have Stunt Double enter the battlefield as a copy of any creature on the battlefield.

When Tomb of Horrors Adventurer enters the battlefield, you take the initiative. Whenever you cast your second spell each turn, copy it. If you've completed a dungeon, copy that spell twice instead. You may choose new targets for the copies. (A copy of a permanent spell becomes a token.)

You may have Undercover Operative enter the battlefield as a copy of any creature on the battlefield, except it enters with a shield counter on it if you control that creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

As Vesuvan Shapeshifter enters the battlefield or is turned face up, you may choose another creature on the battlefield. If you do, until Vesuvan Shapeshifter is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down." Morph {1}{U}

You may have Wall of Stolen Identity enter the battlefield as a copy of any creature on the battlefield, except it's a Wall in addition to its other types and has defender. When you do, tap the copied creature and it doesn't untap during its controller's untap step for as long as you control Wall of Stolen Identity.

Exile a creature card from your graveyard and pay its mana cost: Create a token that's a copy of that card. Activate only as a sorcery.

Enchant creature you control At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1. When enchanted creature dies, if that creature was a Horror, return Endless Evil to its owner's hand.

If Leyline of Anticipation is in your opening hand, you may begin the game with it on the battlefield. You may cast spells as though they had flash.

Enchant creature As Metamorphic Alteration enters the battlefield, choose a creature. Enchanted creature is a copy of the chosen creature.

Return all attacking creatures to their owner's hand.

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

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.

Exile target creature you control, then return that card to the battlefield under its owner's control. Draw a card.

You may cast spells this turn as though they had flash. Draw a card.

Counter target spell.

Choose one — • Counter target artifact or enchantment spell. If a spell is countered this way, exile it instead of putting it into its owner's graveyard. • Counter target activated or triggered ability.

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Create a token that's a copy of target creature you control. If it's your turn, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Return all noncreature, nonland permanents to their owners' hands.

Draw a card for each Island you control, then discard two cards.

Draw two cards, then discard two cards. Untap up to three lands.

Choose target nonlegendary creature. The next time one or more creatures or planeswalkers enter the battlefield this turn, they enter as copies of the chosen creature. Foretell {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.)

Counter target noncreature spell.

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

{T}: Add {C}. {2}, {T}, Sacrifice Demolition Field: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

({T}: Add {U}.)

Lonely Sandbar enters the battlefield tapped. {T}: Add {U}. Cycling {U} ({U}, Discard this card: Draw a card.)

Mirrorpool enters the battlefield tapped. {T}: Add {C}. {2}{C}, {T}, Sacrifice Mirrorpool: Copy target instant or sorcery spell you control. You may choose new targets for the copy. {4}{C}, {T}, Sacrifice Mirrorpool: Create a token that's a copy of target creature you control.

({T}: Add {U}.) Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands. When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

{T}: Add {C}. {2}, {T}, Sacrifice a Desert: Exile all graveyards.

The Surgical Bay enters the battlefield tapped. {T}: Add {U}. {1}{U}, {T}, Sacrifice The Surgical Bay: Draw a card.

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Tempting offer — Choose target creature you control. Create a token that's a copy of that creature. Each opponent may create a token that's a copy of that creature. For each opponent who does, create a token that's a copy of that creature.

Create a token that's a copy of target creature you control. Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

For each creature target player controls, create a token that's a copy of that creature.

At the beginning of your upkeep, you may have Cryptoplasm become a copy of another target creature, except it has this ability.

Enchant artifact you control At the beginning of your upkeep, create a token that's a copy of enchanted artifact. Then if you control eight or more artifacts with the same name as one another, you win the game.