Psychic Symbiont

Flying
When this creature enters, target opponent discards a card and you draw a card.

Plague Mare

This creature can't be blocked by white creatures.
When this creature enters, creatures your opponents control get -1/-1 until end of turn.

Banehound

Slitherwisp

Flash
Whenever you cast another spell that has flash, you draw a card and each opponent loses 1 life.

Foul Watcher

Flying
When this creature enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — This creature gets +1/+0 as long as there are four or more card types among cards in your graveyard.

Void Beckoner

Deathtouch
Cycling {2}{B} ({2}{B}, Discard this card: Draw a card.)
When you cycle this card, put a deathtouch counter on target creature you control.

Devourer of Memory

Whenever one or more cards are put into your graveyard from your library, this creature gets +1/+1 until end of turn and can't be blocked this turn.
{1}{U}{B}: Mill a card.

Grimdancer

This creature enters with your choice of two different counters on it from among menace, deathtouch, and lifelink.

Angel of Suffering

Flying
If damage would be dealt to you, prevent that damage and mill twice that many cards.

Umbris, Fear Manifest

Umbris gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

Faceless Butcher

When this creature enters, exile another target creature.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Dread Presence

Whenever a Swamp you control enters, choose one —
• You draw a card and you lose 1 life.
• This creature deals 2 damage to any target and you gain 2 life.

Hunted Nightmare

Menace
When this creature enters, target opponent puts a deathtouch counter on a creature they control.

Swimmer in Nightmares

This creature gets +3/+0 as long as there are ten or more cards in a single graveyard.
This creature can't be blocked as long as you control an Ashiok planeswalker.

Dream Eater

Flash
Flying
When this creature enters, surveil 4. When you do, you may return target nonland permanent an opponent controls to its owner's hand. (To surveil 4, look at the top four cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Mindleecher

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, exile the top card of each opponent's library face down. You may look at and play those cards for as long as they remain exiled.

Faceless Devourer

Shadow (This creature can block or be blocked by only creatures with shadow.)
When this creature enters, exile another target creature with shadow.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Ashiok's Skulker

{3}{U}: This creature can't be blocked this turn.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)