Bitterblossom

At the beginning of your upkeep, you lose 1 life and create a 1/1 black Faerie Rogue creature token with flying.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Dauthi Voidwalker

Shadow (This creature can block or be blocked by only creatures with shadow.)
If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.
{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Liliana of the Dark Realms

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
−3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.
−6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

Jet Medallion

Black spells you cast cost {1} less to cast.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures of their choice.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Grave Titan

Deathtouch
Whenever Grave Titan enters or attacks, create two 2/2 black Zombie creature tokens.

Demonic Tutor

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

Ulamog, the Ceaseless Hunger

When you cast this spell, exile two target permanents.
Indestructible
Whenever Ulamog, the Ceaseless Hunger attacks, defending player exiles the top twenty cards of their library.

Deserted Temple

{T}: Add {C}.
{1}, {T}: Untap target land.

Praetor's Grasp

Search target opponent's library for a card and exile it face down. Then that player shuffles. You may play that card for as long as it remains exiled.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Damnation

Destroy all creatures. They can't be regenerated.

Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.