Shadow Alley Denizen

Whenever another black creature you control enters, target creature gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Slip On the Ring

Exile target creature you own, then return it to the battlefield under your control. The Ring tempts you.

Flicker of Fate

Exile target creature or enchantment, then return it to the battlefield under its owner's control.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Cauldron Familiar

When this creature enters, each opponent loses 1 life and you gain 1 life.
Sacrifice a Food: Return this card from your graveyard to the battlefield.

Hopeless Nightmare

When this enchantment enters, each opponent discards a card and loses 2 life.
When this enchantment is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice this enchantment.

Azorius Arrester

When this creature 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.)

Barrier of Bones

Defender
When this creature enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Snarling Gorehound

Menace
Whenever another creature you control with power 2 or less enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Cathedral Sanctifier

When this creature enters, you gain 3 life.

Accursed Marauder

When this creature enters, each player sacrifices a nontoken creature of their choice.