Three Tree Mascot

Changeling (This card is every creature type.)
{1}: Add one mana of any color. Activate only once each turn.

Plains

Shapesharer

Changeling (This card is every creature type.)
{2}{U}: Target Shapeshifter becomes a copy of target creature until your next turn.

Primal Plasma

As this creature enters, it becomes your choice of a 3/3 creature, a 2/2 creature with flying, or a 1/6 creature with defender.

Contaminated Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle.
Cycling {W}{U}{B} ({W}{U}{B}, Discard this card: Draw a card.)

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Terramorphic Expanse

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

Exotic Orchard

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

Cemetery Puca

Whenever a creature dies, you may pay {1}. If you do, this creature becomes a copy of that creature, except it has this ability.

Crib Swap

Changeling (This card is every creature type.)
Exile target creature. Its controller creates a 1/1 colorless Shapeshifter creature token with changeling.

Fractured Identity

Exile target nonland permanent. Each player other than its controller creates a token that's a copy of it.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav become a copy of that card, except its name is Lazav, Dimir Mastermind, it's legendary in addition to its other types, and it has hexproof and this ability.

Shadow Kin

Flash
At the beginning of your upkeep, each player mills three cards. You may exile a creature card from among the cards milled this way. If you do, this creature becomes a copy of that card, except it has this ability.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Azorius Signet

Nascent Metamorph

Whenever this creature attacks or blocks, target opponent reveals cards from the top of their library until they reveal a creature card. This creature 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.

The Prismatic Piper

If The Prismatic Piper is your commander, choose a color before the game begins. The Prismatic Piper is the chosen color.
Partner (You can have two commanders if both have partner.)

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Lazav, Familiar Stranger

Whenever you commit a crime, put a +1/+1 counter on Lazav. Then you may exile a card from a graveyard. If a creature card was exiled this way, you may have Lazav become a copy of that card until end of turn. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Path of Ancestry

This land enters 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.)

Clone Shell

Imprint — When this creature enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom of your library in any order.
When this creature dies, turn the exiled card face up. If it's a creature card, put it onto the battlefield under your control.

Unstable Shapeshifter

Whenever another creature enters, this creature becomes a copy of that creature, except it has this ability.

Mirrorweave

Each other creature becomes a copy of target nonlegendary creature until end of turn.

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.")

Valiant Changeling

This spell costs {1} less to cast for each creature type among creatures you control. This effect can't reduce the amount of mana this spell costs by more than {5}.
Changeling (This card is every creature type.)
Double strike

Aetherling

{U}: Exile this creature. Return it to the battlefield under its owner's control at the beginning of the next end step.
{U}: This creature can't be blocked this turn.
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Wayfarer's Bauble

{2}, {T}, Sacrifice this artifact: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Bloodline Pretender

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on this creature.

Phyrexian Metamorph

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

Vesuva

You may have this land enter tapped as a copy of any land on the battlefield.

Unsettled Mariner

Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Callidus Assassin

Flash
Polymorphine — You may have this creature enter tapped as a copy of any creature on the battlefield, except it has "When this creature enters, destroy up to one other target creature with the same name as this creature."

Didn't Say Please

Counter target spell. Its controller mills three cards.

Volrath the Fallen

{1}{B}, Discard a creature card: Volrath gets +X/+X until end of turn, where X is the discarded card's mana value.

Cairn Wanderer

Changeling (This card is every creature type.)
As long as a creature card with flying is in a graveyard, this creature has flying. The same is true for fear, first strike, double strike, deathtouch, haste, landwalk, lifelink, protection, reach, trample, shroud, and vigilance.

Orzhov Signet

Sol Talisman

Suspend 3—{1} (Rather than cast this card from your hand, pay {1} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
{T}: Add {C}{C}.

Arcane Signet

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

Metallic Mimic

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Morphling

{U}: Untap this creature.
{U}: This creature gains flying until end of turn.
{U}: This creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Evil Twin

You may have this creature enter 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."

Command Tower

Anthroplasm

This creature enters with two +1/+1 counters on it.
{X}, {T}: Remove all +1/+1 counters from this creature and put X +1/+1 counters on it.

Escaped Shapeshifter

As long as an opponent controls a creature with flying not named Escaped Shapeshifter, this creature has flying. The same is true for first strike, trample, and protection from any color.

Swamp

Sculpting Steel

You may have this artifact enter as a copy of any artifact on the battlefield.

Zygon Infiltrator

Body-print — {2}{U}: Tap another target creature and put a stun counter on it. This creature becomes a copy of that creature for as long as that creature remains tapped. Activate only as a sorcery. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Wall of Stolen Identity

You may have this creature enter 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 this creature.

Lazav, Wearer of Faces

Whenever Lazav attacks, exile target card from a graveyard, then investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, you may have Lazav become a copy of a creature card exiled with it until end of turn.

Halfdane

At the beginning of your upkeep, change Halfdane's base power and toughness to the power and toughness of target creature other than Halfdane until the end of your next upkeep.

Fellwar Stone

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Renegade Doppelganger

Whenever another creature you control enters, you may have this creature become a copy of that creature until end of turn. (If it does, it loses this ability for the rest of the turn.)

Shapeshifter's Marrow

At the beginning of each opponent's upkeep, that player reveals the top card of their library. If it's a creature card, the player puts the card into their graveyard and this enchantment becomes a copy of that card. (If it does, it loses this ability.)

Mirage Mirror

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

Mirror Mockery

Enchant creature
Whenever enchanted creature attacks, you may create a token that's a copy of that creature. Exile that token at end of combat.

Cryptoplasm

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

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

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.

Dimir Signet

Duplicant

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

Corrupted Shapeshifter

Devoid (This card has no color.)
As this creature enters, it becomes your choice of a 3/3 creature with flying, a 2/5 creature with vigilance, or a 0/12 creature with defender.

Littjara Kinseekers

Changeling (This card is every creature type.)
When this creature enters, if you control three or more creatures that share a creature type, put a +1/+1 counter on this creature, then scry 1.

Vesuvan Drifter

Flying
You may look at the top card of your library any time.
At the beginning of each combat, you may reveal the top card of your library. If you reveal a creature card this way, this creature becomes a copy of that card until end of turn, except it has flying.

Identity Thief

Whenever this creature attacks, you may exile another target nontoken creature. If you do, this creature 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.

Urza's Avenger

{0}: This creature gets -1/-1 and gains your choice of banding, flying, first strike, or trample until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Glasspool Shore

Glasspool Mimic

You may have this creature enter as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Mimic // Glasspool Shore

Quicksilver Gargantuan

You may have this creature enter as a copy of any creature on the battlefield, except it's 7/7.

Endling

{B}: This creature gains menace until end of turn.
{B}: This creature gains deathtouch until end of turn.
{B}: This creature gains undying until end of turn. (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)
{1}: This creature gets +1/-1 or -1/+1 until end of turn.

Brightling

{W}: This creature gains vigilance until end of turn.
{W}: This creature gains lifelink until end of turn.
{W}: Return this creature to its owner's hand.
{1}: This creature gets +1/-1 or -1/+1 until end of turn.

Shapeshifter

As this creature enters, choose a number between 0 and 7.
At the beginning of your upkeep, you may choose a number between 0 and 7.
Shapeshifter's power is equal to the last chosen number and its toughness is equal to 7 minus that number.

Evolving Wilds

Shape Stealer

Whenever this creature blocks or becomes blocked by a creature, change this creature's base power and toughness to that creature's power and toughness until end of turn.

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Volrath's Shapeshifter

As long as the top card of your graveyard is a creature card, this creature has the full text of that card and has the text "{2}: Discard a card." (This creature has that card's name, mana cost, color, types, abilities, power, and toughness.)
{2}: Discard a card.

Jodah's Avenger

{0}: Until end of turn, this creature gets -1/-1 and gains your choice of double strike, protection from red, vigilance, or shadow. (A creature with shadow can block or be blocked by only creatures with shadow.)

Void Rend

This spell can't be countered.
Destroy target nonland permanent.

Island

Primal Clay

As this creature enters, it becomes your choice of a 3/3 artifact creature, a 2/2 artifact creature with flying, or a 1/6 Wall artifact creature with defender in addition to its other types. (A creature with defender can't attack.)