Cavern Harpy

Flying
When Cavern Harpy enters, return a blue or black creature you control to its owner's hand.
Pay 1 life: Return Cavern Harpy to its owner's hand.

Silver Drake

Flying
When Silver Drake enters, return a white or blue creature you control to its owner's hand.

Stonehorn Dignitary

When Stonehorn Dignitary enters, target opponent skips their next combat phase.

Burglar Rat

When this creature enters, each opponent discards a card.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Azorius Arrester

When Azorius Arrester enters, detain target creature an opponent controls. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)

Cathedral Sanctifier

When Cathedral Sanctifier enters, you gain 3 life.

Auramancer

When Auramancer enters, you may return target enchantment card from your graveyard to your hand.

Archaeomender

When Archaeomender enters, return target artifact card from your graveyard to your hand.

Archaeomancer

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

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Architects of Will

When Architects of Will enters, look at the top three cards of target player's library, then put them back in any order.
Cycling {U/B} ({U/B}, Discard this card: Draw a card.)

Steel Leaf Paladin

First strike
When Steel Leaf Paladin enters, return a green or white creature you control to its owner's hand.

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Aether Adept

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

Escape Routes

{2}{U}: Return target white or black creature you control to its owner's hand.

Shrieking Drake

Flying
When Shrieking Drake enters, return a creature you control to its owner's hand.

Augur of Bolas

When Augur of Bolas 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.

Augury Owl

Flying
When Augury Owl enters, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Sage of Epityr

When Sage of Epityr enters, look at the top four cards of your library, then put them back in any order.