You may have Sakashima of a Thousand Faces enter the battlefield as a copy of another creature you control, except it has Sakashima of a Thousand Faces's other abilities. The "legend rule" doesn't apply to permanents you control. Partner (You can have two commanders if both have partner.)

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

{1}, {T}: Add {W}{U}.

Charcoal Diamond enters the battlefield tapped. {T}: Add {B}.

{3}, {T} or {U}, {T}: Return target creature to its owner's hand unless its controller pays {1}.

{2}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy. {3}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy. {4}, {T}: Copy target permanent spell you control. (The copy becomes a token.)

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you. {T}: Add {C}{C}.

Mana Vault doesn't untap during your untap step. At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault. At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you. {T}: Add {C}{C}{C}.

Marble Diamond enters the battlefield tapped. {T}: Add {W}.

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.

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

{1}, {T}: Add {W}{B}.

Sky Diamond enters the battlefield tapped. {T}: Add {U}.

Kicker {3} Indestructible When Skyclave Relic enters the battlefield, if it was kicked, create two tapped tokens that are copies of Skyclave Relic. {T}: Add one mana of any color.

{T}: Add {C}{C}.

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.

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.) As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Imprint — When Duplicant enters the battlefield, you may exile target nontoken creature. As long as a card exiled with Duplicant is a creature card, Duplicant has the power, toughness, and creature types of the last creature card exiled with Duplicant. It's still a Shapeshifter.

You may have Evil Twin enter the battlefield as a copy of any creature on the battlefield, except it has "{U}{B}, {T}: Destroy target creature with the same name as this creature."

Deathtouch When Gonti, Lord of Luxury enters the battlefield, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast it.

Flash If an opponent would draw a card except the first one they draw in each of their draw steps, instead you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Flying When Mulldrifter enters the battlefield, draw two cards. Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Flash If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Flash You control your opponents while they're searching their libraries. While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

You may have Phantasmal Image enter the battlefield as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

({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.

You may have Sakashima the Impostor enter the battlefield as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."

At the beginning of your upkeep, choose target opponent. This turn, that player can't cast spells or activate abilities and plays with their hand revealed. You may play lands and cast spells from that player's hand this turn.

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.

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}

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.

Whenever an opponent casts their first spell each turn, that player exiles the top card of their library. If it's a nonland card, you may cast it without paying its mana cost.

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.

Draw three cards, then put two cards from your hand on top of your library in any order.

Counter target spell.

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

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

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

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

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

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Choose one or more — • Counter target spell. • Counter target activated or triggered ability. • Return target nonland permanent to its owner's hand. • Create a token that's a copy of target creature you control. • Target player draws a card.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Castle Locthwain enters the battlefield tapped unless you control a Swamp. {T}: Add {B}. {1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

{T}: Add {C}. {T}: Add {W} or {B}. Caves of Koilos deals 1 damage to you.

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

Creeping Tar Pit enters the battlefield tapped. {T}: Add {U} or {B}. {1}{U}{B}: Creeping Tar Pit becomes a 3/2 blue and black Elemental creature until end of turn and can't be blocked this turn. It's still a land.

{1}, {T}: Add {U}{B}.

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

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Halimar Depths enters the battlefield tapped. When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order. {T}: Add {U}.

{T}: Add {C}. {T}, Sacrifice a creature: You gain 1 life.

({T}: Add {W} or {U}.) Irrigated Farmland enters the battlefield tapped. Cycling {2} ({2}, Discard this card: Draw a card.)

({T}: Add {U}.)

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

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.

Path of Ancestry enters the battlefield tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

({T}: Add {W}.)

({T}: Add {W} or {U}.) Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

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

Shambling Vent enters the battlefield tapped. {T}: Add {W} or {B}. {1}{W}{B}: Shambling Vent becomes a 2/3 white and black Elemental creature with lifelink until end of turn. It's still a land.

({T}: Add {U} or {B}.) Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

({T}: Add {B}.)

{T}: Add {C}. {T}: Add {W} or {B}. Activate only if you control a Swamp.

Temple of Deceit enters the battlefield tapped. When Temple of Deceit enters the battlefield, scry 1. {T}: Add {U} or {B}.

{T}: Add {C}{C}. Activate only if you control five or more lands.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}: Add {C}. {T}: Add {U} or {B}. Underground River deals 1 damage to you.

Vault of Champions enters the battlefield tapped unless you have two or more opponents. {T}: Add {W} or {B}.

Each opponent can't draw more than one card each turn. −2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Choose one — • Destroy all Dragon creatures. • Destroy all non-Dragon creatures.

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Search your library for a card, put that card into your hand, then shuffle.

As an additional cost to cast this spell, sacrifice a creature. Search your library for a card, put that card into your hand, then shuffle.

Destroy all creatures you don't control and all planeswalkers you don't control.

Create a token that's a copy of target creature you control. Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Scry 2, then draw two cards. You lose 2 life.

Kicker {5} (You may pay an additional {5} as you cast this spell.) Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Destroy all creatures and planeswalkers except for commanders.

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.

Return a creature you control to its owner's hand, then destroy all creatures.