Soulcatchers' Aerie

Whenever a Bird is put into your graveyard from the battlefield, put a feather counter on Soulcatchers' Aerie.
Bird creatures get +1/+1 for each feather counter on Soulcatchers' Aerie.

Mistwalker

Changeling (This card is every creature type.)
Flying
{1}{U}: Mistwalker gets +1/-1 until end of turn.

Mirror Image

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

Boldwyr Intimidator

Cowards can't block Warriors.
{R}: Target creature becomes a Coward until end of turn.
{2}{R}: Target creature becomes a Warrior until end of turn.

Birthing Boughs

{4}, {T}: Create a 2/2 colorless Shapeshifter creature token with changeling. (It has every creature type.)

Harmonic Sliver

All Slivers have "When this permanent enters the battlefield, destroy target artifact or enchantment."

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

Forest

Arcane Sanctum

Arcane Sanctum enters the battlefield tapped.
{T}: Add {W}, {U}, or {B}.

Seaside Citadel

Seaside Citadel enters the battlefield tapped.
{T}: Add {G}, {W}, or {U}.

Crib Swap

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

Eladamri's Call

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

Jodah's Avenger

{0}: Until end of turn, Jodah's Avenger 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.)

Clone

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

Littjara Kinseekers

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

Reaper King

({2/W} can be paid with any two mana or with {W}. This card's mana value is 10.)
Other Scarecrow creatures you control get +1/+1.
Whenever another Scarecrow enters the battlefield under your control, destroy target permanent.

Arcane Adaptation

As Arcane Adaptation enters the battlefield, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Kolaghan, the Storm's Fury

Flying
Whenever a Dragon you control attacks, creatures you control get +1/+0 until end of turn.
Dash {3}{B}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Gladewalker Ritualist

Changeling (This card is every creature type.)
Whenever another creature named Gladewalker Ritualist enters the battlefield under your control, draw a card.

Song-Mad Ruins

Song-Mad Ruins enters the battlefield tapped.
{T}: Add {R}.

Song-Mad Treachery

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

Song-Mad Treachery // Song-Mad Ruins

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh, Criosphinx Sovereign or another Sphinx enters the battlefield under your control, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Malakir Mire

Malakir Mire enters the battlefield tapped.
{T}: Add {B}.

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Universal Automaton

Changeling (This card is every creature type.)

Dack's Duplicate

You may have Dack's Duplicate enter the battlefield as a copy of any creature on the battlefield, except it has haste and dethrone. (Whenever it attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)

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}.

Pack Leader

Other Dogs you control get +1/+1.
Whenever Pack Leader attacks, prevent all combat damage that would be dealt this turn to Dogs you control.

Chromatic Lantern

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

Risen Reef

Whenever Risen Reef or another Elemental enters the battlefield under your control, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Crumbling Necropolis

Crumbling Necropolis enters the battlefield tapped.
{T}: Add {U}, {B}, or {R}.

Littjara Mirrorlake

Littjara Mirrorlake enters the battlefield tapped.
{T}: Add {U}.
{2}{G}{G}{U}, {T}, Sacrifice Littjara Mirrorlake: Create a token that's a copy of target creature you control, except it enters the battlefield with an additional +1/+1 counter on it. Activate only as a sorcery.

Jwari Ruins

Jwari Ruins enters the battlefield tapped.
{T}: Add {U}.

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters the battlefield, choose a creature type.
Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Shapesharer

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

Path of Ancestry

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.)

Savage Lands

Savage Lands enters the battlefield tapped.
{T}: Add {B}, {R}, or {G}.

Sylvia Brightspear

Partner with Khorvath Brightflame (When this creature enters the battlefield, target player may put Khorvath into their hand from their library, then shuffle.)
Double strike
Dragons your team controls have double strike.

Silumgar, the Drifting Death

Flying, hexproof
Whenever a Dragon you control attacks, creatures defending player controls get -1/-1 until end of turn.

Dermoplasm

Flying
Morph {2}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Dermoplasm is turned face up, you may put a creature card with a morph ability from your hand onto the battlefield face up. If you do, return Dermoplasm to its owner's hand.

Biogenic Ooze

When Biogenic Ooze enters the battlefield, create a 2/2 green Ooze creature token.
At the beginning of your end step, put a +1/+1 counter on each Ooze you control.
{1}{G}{G}{G}: Create a 2/2 green Ooze creature token.

Reflections of Littjara

As Reflections of Littjara enters the battlefield, 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.)

Blades of Velis Vel

Changeling (This card is every creature type.)
Up to two target creatures each get +2/+0 and gain all creature types until end of turn.

Ayula, Queen Among Bears

Whenever another Bear enters the battlefield under your control, choose one —
• Put two +1/+1 counters on target Bear.
• Target Bear you control fights target creature you don't control.

Clone Shell

Imprint — When Clone Shell enters the battlefield, 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 Clone Shell dies, turn the exiled card face up. If it's a creature card, put it onto the battlefield under your control.

Khorvath Brightflame

Partner with Sylvia Brightspear (When this creature enters the battlefield, target player may put Sylvia into their hand from their library, then shuffle.)
Flying, haste
Knights your team controls have flying and haste.

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters the battlefield, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Cloudshredder Sliver

Sliver creatures you control have flying and haste.

Masked Vandal

Changeling (This card is every creature type.)
When Masked Vandal enters the battlefield, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on Taurean Mauler.

Liliana's Contract

When Liliana's Contract enters the battlefield, you draw four cards and you lose 4 life.
At the beginning of your upkeep, if you control four or more Demons with different names, you win the game.

Dragon's Hoard

Whenever a Dragon enters the battlefield under your control, put a gold counter on Dragon's Hoard.
{T}, Remove a gold counter from Dragon's Hoard: Draw a card.
{T}: Add one mana of any color.

Manaweft Sliver

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

Swamp

Yuriko, the Tiger's Shadow

Commander ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters the battlefield, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Irregular Cohort

Changeling (This card is every creature type.)
When Irregular Cohort enters the battlefield, create a 2/2 colorless Shapeshifter creature token with changeling.

Magda, Brazen Outlaw

Other Dwarves you control get +1/+0.
Whenever a Dwarf you control becomes tapped, create a Treasure token.
Sacrifice five Treasures: Search your library for an artifact or Dragon card, put that card onto the battlefield, then shuffle.

Command Tower

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

Plains

Eureka Moment

Draw two cards. You may put a land card from your hand onto the battlefield.

Morphling

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

Ingenious Infiltrator

Ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, draw a card.

Metallic Mimic

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

Sea Gate Loremaster

{T}: Draw a card for each Ally you control.

Mountain

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav, Dimir Mastermind 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.

The World Tree

The World Tree enters the battlefield tapped.
{T}: Add {G}.
As long as you control six or more lands, lands you control have "{T}: Add one mana of any color."
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice The World Tree: Search your library for any number of God cards, put them onto the battlefield, then shuffle.

Impostor of the Sixth Pride

Jungle Shrine

Jungle Shrine enters the battlefield tapped.
{T}: Add {R}, {G}, or {W}.

Arcane Signet

Island

Urza's Incubator

As Urza's Incubator enters the battlefield, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Knights' Charge

Whenever a Knight you control attacks, each opponent loses 1 life and you gain 1 life.
{6}{W}{B}, Sacrifice Knights' Charge: Return all Knight creature cards from your graveyard to the battlefield.

Cast Off

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)

Realm-Cloaked Giant

Realm-Cloaked Giant // Cast Off

Venomous Changeling

Changeling (This card is every creature type.)
Deathtouch

Species Specialist

As Species Specialist enters the battlefield, choose a creature type.
Whenever a creature of the chosen type dies, you may draw a card.