Exsanguinate

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

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Tainted Aether

Whenever a creature enters the battlefield, its controller sacrifices a creature or land.

Fires of Invention

You can cast spells only during your turn and you can cast no more than two spells each turn.
You may cast spells with mana value less than or equal to the number of lands you control without paying their mana costs.

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

No Mercy

Whenever a creature deals damage to you, destroy it.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Grave Betrayal

Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Heat Stroke

At end of combat, destroy each creature that blocked or was blocked this turn.

Mogis, God of Slaughter

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Underworld Connections

Enchant land
Enchanted land has "{T}, Pay 1 life: Draw a card."

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

Skeletal Scrying

As an additional cost to cast this spell, exile X cards from your graveyard.
You draw X cards and you lose X life.

Bottled Cloister

At the beginning of each opponent's upkeep, exile all cards from your hand face down.
At the beginning of your upkeep, return all cards you own exiled with Bottled Cloister to your hand, then draw a card.

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with Possibility Storm on the bottom of their library in a random order.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Spreading Plague

Whenever a creature enters the battlefield, destroy all other creatures that share a color with it. They can't be regenerated.

Greed

Total War

Whenever a player attacks with one or more creatures, destroy all untapped non-Wall creatures that player controls that didn't attack, except for creatures the player hasn't controlled continuously since the beginning of the turn.

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.