Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Drown in Shapelessness

Return target creature to its owner's hand.

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Arrester's Admonition

Return target creature to its owner's hand.
Addendum — If you cast this spell during your main phase, draw a card.

Glen Elendra Pranksters

Flying
Whenever you cast a spell during an opponent's turn, you may return target creature you control to its owner's hand.

Leyline of Transformation

If Leyline of Transformation is in your opening hand, you may begin the game with it on the battlefield.
As Leyline of Transformation enters, 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.

Whirlpool Whelm

Clash with an opponent, then return target creature to its owner's hand. If you win, you may put that creature on top of its owner's library instead. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Boing!

Return target creature to its owner's hand, then roll a six-sided die. If the result is 3 or less, scry a number of cards equal to the result.

Naru Meha, Master Wizard

Flash
When Naru Meha, Master Wizard enters, copy target instant or sorcery spell you control. You may choose new targets for the copy.
Other Wizards you control get +1/+1.

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Aether Adept

When Aether Adept enters, return target creature to its owner's hand.

Erratic Portal

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

Unexplained Disappearance

Return target creature to its owner's hand.
Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Stolen by the Fae

Return target creature with mana value X to its owner's hand. You create X 1/1 blue Faerie creature tokens with flying.

Pol Jamaar, Illusionist

Flying
When Pol Jamaar, Illusionist enters, choose a creature type. Draw a card for each creature you control of that type.

Mystic Sanctuary

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

Cynette, Jelly Drover

When Cynette, Jelly Drover enters or dies, create a 1/1 blue Jellyfish creature token with flying.
Creatures you control with flying get +1/+1.

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Jace, the Mind Sculptor

+2: Look at the top card of target player's library. You may put that card on the bottom of that player's library.
0: Draw three cards, then put two cards from your hand on top of your library in any order.
−1: Return target creature to its owner's hand.
−12: Exile all cards from target player's library, then that player shuffles their hand into their library.

Separatist Voidmage

When Separatist Voidmage enters, you may return target creature to its owner's hand.

Banner of Kinship

As this artifact enters, choose a creature type. This artifact enters with a fellowship counter on it for each creature you control of the chosen type.
Creatures you control of the chosen type get +1/+1 for each fellowship counter on this artifact.

Sapphire Medallion

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

Silent Departure

Return target creature to its owner's hand.
Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Symbol of Unsummoning

Return target creature to its owner's hand.
Draw a card.

Portal of Sanctuary

{1}, {T}: Return target creature you control and each Aura attached to it to their owners' hands. Activate only during your turn.

Peel from Reality

Return target creature you control and target creature you don't control to their owners' hands.

Door of Destinies

As Door of Destinies enters, 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.

Escape Detection

Freerunning—Return a blue creature you control to its owner's hand. (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Return target creature to its owner's hand.
Draw a card.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Pillar of Origins

As Pillar of Origins enters, choose a creature type.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Unsummon

Temporal Machinations

Return target creature to its owner's hand. If you control an artifact, draw a card.

Reflections of Littjara

As Reflections of Littjara 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.)

Aether Spellbomb

{U}, Sacrifice Aether Spellbomb: Return target creature to its owner's hand.
{1}, Sacrifice Aether Spellbomb: Draw a card.

Just the Wind

Return target creature to its owner's hand.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Lumengrid Drake

Flying
Metalcraft — When Lumengrid Drake enters, if you control three or more artifacts, return target creature to its owner's hand.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Equilibrium

Whenever you cast a creature spell, you may pay {1}. If you do, return target creature to its owner's hand.

Call to Heel

Return target creature to its owner's hand. Its controller draws a card.

Linessa, Zephyr Mage

{X}{U}{U}, {T}: Return target creature with mana value X to its owner's hand.
Grandeur — Discard another card named Linessa, Zephyr Mage: Target player returns a creature they control to its owner's hand, then repeats this process for an artifact, an enchantment, and a land.

Crashing Tide

This spell has flash as long as you control a Merfolk.
Return target creature to its owner's hand.
Draw a card.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Arcane Adaptation

As Arcane Adaptation enters, 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.

Consuming Vortex

Return target creature to its owner's hand.
Splice onto Arcane {3}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Jace, Unraveler of Secrets

+1: Scry 1, then draw a card.
−2: Return target creature to its owner's hand.
−8: You get an emblem with "Whenever an opponent casts their first spell each turn, counter that spell."

Repulse

Decoction Module

Whenever a creature you control enters, you get {E} (an energy counter).
{4}, {T}: Return target creature you control to its owner's hand.

Crystal Shard

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

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Island

Clutch of Currents

Return target creature to its owner's hand.
Awaken 3—{4}{U} (If you cast this spell for {4}{U}, also put three +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Man-o'-War

When Man-o'-War enters, return target creature to its owner's hand.

Fading Hope

Return target creature to its owner's hand. If its mana value was 3 or less, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Voidwielder

When Voidwielder enters, you may return target creature to its owner's hand.

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Progenitor's Icon

As Progenitor's Icon enters, choose a creature type.
{T}: Add one mana of any color.
{T}: The next spell of the chosen type you cast this turn can be cast as though it had flash.

Naban, Dean of Iteration

If a Wizard you control entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Drag Under

Sage-Eye Avengers

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Sage-Eye Avengers attacks, you may return target creature to its owner's hand if its power is less than Sage-Eye Avengers's power.

Mirror Box

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.

Urza's Incubator

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

Rite of Replication

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.

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Word of Undoing

Return target creature and all white Auras you own attached to it to their owners' hands.

Voyage's End

Return target creature to its owner's hand. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Xenograft

As Xenograft enters, choose a creature type.
Each creature you control is the chosen type in addition to its other types.

Snapback

You may exile a blue card from your hand rather than pay this spell's mana cost.
Return target creature to its owner's hand.

Depths of Desire

Return target creature to its owner's hand. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")