Panharmonicon

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

Augur of Bolas

When this creature enters, look at the top three cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Omniscience

You may cast spells from your hand without paying their mana costs.

Erratic Portal

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

Archaeomancer

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

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.

Arcane Proxy

Prototype {1}{U}{U} — 2/1 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When this creature enters, if you cast it, exile target instant or sorcery card with mana value less than or equal to this creature's power from your graveyard. Copy that card. You may cast the copy without paying its mana cost.

Umbilicus

At the beginning of each player's upkeep, that player may pay 2 life. If they don't, they return a permanent they control to its owner's hand.

Merchant of Secrets

Merfolk Trickster

Flash
When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Blood Clock

At the beginning of each player's upkeep, that player returns a permanent they control to its owner's hand unless they pay 2 life.

Aether Adept

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

Naru Meha, Master Wizard

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

Exclusion Mage

When this creature enters, return target creature an opponent controls to its owner's hand.

Sower of Temptation

Flying
When this creature enters, gain control of target creature for as long as this creature remains on the battlefield.

Portal Mage

Flash
When this creature enters during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or their permanents.)

Aven Fogbringer

Flying
When this creature enters, return target land to its owner's hand.

Ingenious Prodigy

Skulk (This creature can't be blocked by creatures with greater power.)
This creature enters with X +1/+1 counters on it.
At the beginning of your upkeep, if this creature has one or more +1/+1 counters on it, you may remove a +1/+1 counter from it. If you do, draw a card.

Barrin, Tolarian Archmage

When Barrin enters, return up to one other target creature or planeswalker to its owner's hand.
At the beginning of your end step, if a permanent was put into your hand from the battlefield this turn, draw a card.

Galecaster Colossus

Tap an untapped Wizard you control: Return target nonland permanent you don't control to its owner's hand.

Cloudkin Seer

Flying
When this creature enters, draw a card.

Archive Dragon

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When this creature enters, scry 2.

Gadwick, the Wizened

When Gadwick enters, draw X cards.
Whenever you cast a blue spell, tap target nonland permanent an opponent controls.

Inga Rune-Eyes

When Inga Rune-Eyes enters, scry 3.
When Inga Rune-Eyes dies, draw three cards if three or more creatures died this turn.

Faerie Seer

Flying
When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Eternal Skylord

When this creature enters, amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
Zombie tokens you control have flying.

Venser, Shaper Savant

Flash (You may cast this spell any time you could cast an instant.)
When Venser enters, return target spell or permanent to its owner's hand.

Aether Channeler

When this creature enters, choose one —
• Create a 1/1 white Bird creature token with flying.
• Return another target nonland permanent to its owner's hand.
• Draw a card.

Spawnbroker

When this creature enters, you may exchange control of target creature you control and target creature with power less than or equal to that creature's power an opponent controls.

Neurok Invisimancer

This creature can't be blocked.
When this creature enters, target creature can't be blocked this turn.

Harbinger of the Tides

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

Spellseeker

When this creature enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Kaho, Minamo Historian

When Kaho enters, search your library for up to three instant cards, exile them, then shuffle.
{X}, {T}: You may cast a spell with mana value X from among cards exiled with Kaho without paying its mana cost.

Micromancer

When this creature enters, you may search your library for an instant or sorcery card with mana value 1, reveal it, put it into your hand, then shuffle.

Cyclone Summoner

When this creature enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Azami, Lady of Scrolls

Tap an untapped Wizard you control: Draw a card.

Frost Trickster

Flying
When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Archmage of Echoes

Flying, ward {2}
Whenever you cast a Faerie or Wizard permanent spell, copy it. (The copy becomes a token.)