Adaptive Automaton

As Adaptive Automaton enters the battlefield, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Thornwatch Scarecrow

Thornwatch Scarecrow has wither as long as you control a green creature. (It deals damage to creatures in the form of -1/-1 counters.)
Thornwatch Scarecrow has vigilance as long as you control a white creature.

Chromatic Lantern

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

Heap Doll

Sacrifice Heap Doll: Exile target card from a graveyard.

Painter's Servant

As Painter's Servant enters the battlefield, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Consulate Crackdown

When Consulate Crackdown enters the battlefield, exile all artifacts your opponents control until Consulate Crackdown leaves the battlefield.

Rakdos Signet

Door of Destinies

As Door of Destinies enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Orzhov Signet

Blind Obedience

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter the battlefield tapped.

Rattleblaze Scarecrow

Rattleblaze Scarecrow has persist as long as you control a black creature. (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.)
Rattleblaze Scarecrow has haste as long as you control a red creature.

Crawlspace

No more than two creatures can attack you each combat.

Sol Ring

Negate

Quicksmith Genius

Whenever an artifact enters the battlefield under your control, you may discard a card. If you do, draw a card.

Scuttlemutt

{T}: Add one mana of any color.
{T}: Target creature becomes the color or colors of your choice until end of turn.

Plains

Thought Vessel

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

Chromanticore

Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike, vigilance, trample, lifelink
Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

One-Eyed Scarecrow

Defender
Creatures with flying your opponents control get -1/-0.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Island

Counterspell

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.

Tithe

Search your library for a Plains card. If target opponent controls more lands than you, you may search your library for an additional Plains card. Reveal those cards, put them into your hand, then shuffle.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Wild-Field Scarecrow

Defender
{2}, Sacrifice Wild-Field Scarecrow: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature enters the battlefield under your control, create a 2/2 white Unicorn creature token.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Gruul Signet

Golgari Signet

Wingrattle Scarecrow

Wingrattle Scarecrow has flying as long as you control a blue creature.
Wingrattle Scarecrow has persist as long as you control a black creature. (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.)

Blazethorn Scarecrow

Blazethorn Scarecrow has haste as long as you control a red creature.
Blazethorn Scarecrow has wither as long as you control a green creature. (It deals damage to creatures in the form of -1/-1 counters.)

Manalith

Metallic Rebuke

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.

Vraska's Contempt

Exile target creature or planeswalker. You gain 2 life.

Watchwing Scarecrow

Watchwing Scarecrow has vigilance as long as you control a white creature.
Watchwing Scarecrow has flying as long as you control a blue creature.

Boros Signet

Mana Geode

When Mana Geode enters the battlefield, scry 1.
{T}: Add one mana of any color.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Doom Foretold

At the beginning of each player's upkeep, that player sacrifices a nonland, nontoken permanent. If that player can't, they discard a card, they lose 2 life, you draw a card, you gain 2 life, you create a 2/2 white Knight creature token with vigilance, then you sacrifice Doom Foretold.

Forest

Demonic Tutor

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

Kindred Charge

Choose a creature type. For each creature you control of the chosen type, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Scaretiller

Whenever Scaretiller becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.

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.

Wicker Witch

Lurebound Scarecrow

As Lurebound Scarecrow enters the battlefield, choose a color.
When you control no permanents of the chosen color, sacrifice Lurebound Scarecrow.

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: Fire-Belly Changeling gets +1/+0 until end of turn. Activate no more than twice each turn.

Mountain

Lockjaw Snapper

Wither (This deals damage to creatures in the form of -1/-1 counters.)
When Lockjaw Snapper dies, put a -1/-1 counter on each creature with a -1/-1 counter on it.

Sculpting Steel

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

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Thran Dynamo

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice Aura of Silence: Destroy target artifact or enchantment.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Field Creeper

Disallow

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

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.")

Riddlesmith

Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

Snow-Covered Swamp

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Bontu's Last Reckoning

Destroy all creatures. Lands you control don't untap during your next untap step.