Reaper from the Abyss

Flying
Morbid — At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.

Megrim

Whenever an opponent discards a card, this enchantment deals 2 damage to that player.

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Nyxathid

As this creature enters, choose an opponent.
This creature gets -1/-1 for each card in the chosen player's hand.

Drudge Skeletons

{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Kothophed, Soul Hoarder

Flying
Whenever a permanent owned by another player is put into a graveyard from the battlefield, you draw a card and you lose 1 life.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To 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.)

Despise

Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.

Swamp

Succumb to Temptation

Wrench Mind

Target player discards two cards unless they discard an artifact card.

Ravenous Rats

When this creature enters, target opponent discards a card.

Sign in Blood

Target player draws two cards and loses 2 life.

Liliana's Specter

Flying
When this creature enters, each opponent discards a card.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Vampire Nighthawk

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Guul Draz Specter

Flying
This creature gets +3/+3 as long as an opponent has no cards in hand.
Whenever this creature deals combat damage to a player, that player discards a card.

Underworld Dreams

Whenever an opponent draws a card, this enchantment deals 1 damage to that player.

Abyssal Nocturnus

Whenever an opponent discards a card, this creature gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Ancient Craving

You draw three cards and you lose 3 life.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Damnable Pact

Target player draws X cards and loses X life.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Augur of Skulls

{1}{B}: Regenerate this creature.
Sacrifice this creature: Target player discards two cards. Activate only during your upkeep.

Hollowborn Barghest

At the beginning of your upkeep, if you have no cards in hand, each opponent loses 2 life.
At the beginning of each opponent's upkeep, if that player has no cards in hand, they lose 2 life.

Ostracize

Target opponent reveals their hand. You choose a creature card from it. That player discards that card.