Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Captive Audience

Captive Audience enters under the control of an opponent of your choice.
At the beginning of your upkeep, choose one that hasn't been chosen —
• Your life total becomes 4.
• Discard your hand.
• Each opponent creates five 2/2 black Zombie creature tokens.

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Blood Sun

When Blood Sun enters, draw a card.
All lands lose all abilities except mana abilities.

Aphemia, the Cacophony

Flying
At the beginning of your end step, you may exile an enchantment card from your graveyard. If you do, create a 2/2 black Zombie creature token.

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Court of Ambition

When Court of Ambition enters, you become the monarch.
At the beginning of your upkeep, each opponent loses 3 life unless they discard a card. If you're the monarch, instead each opponent loses 6 life unless they discard two cards.

Bitterblossom

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

Blood Moon

Anax, Hardened in the Forge

Anax's power is equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
Whenever Anax or another nontoken creature you control dies, create a 1/1 red Satyr creature token with "This creature can't block." If the creature had power 4 or greater, create two of those tokens instead.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.

Court of Ire

When Court of Ire enters, you become the monarch.
At the beginning of your upkeep, Court of Ire deals 2 damage to any target. If you're the monarch, it deals 7 damage instead.

Cunning Rhetoric

Whenever an opponent attacks you and/or one or more planeswalkers you control, exile the top card of that player's library. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast it.

Baneful Omen

At the beginning of your end step, you may reveal the top card of your library. If you do, each opponent loses life equal to that card's mana value.

Mountain

Ancient Runes

At the beginning of each player's upkeep, Ancient Runes deals damage to that player equal to the number of artifacts they control.

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.

Cruel Reality

Enchant player
At the beginning of enchanted player's upkeep, that player sacrifices a creature or planeswalker. If the player can't, they lose 5 life.

Bitter Feud

As Bitter Feud enters, choose two players.
If a source controlled by one of the chosen players would deal damage to the other chosen player or a permanent that player controls, that source deals double that damage to that player or permanent instead.

An-Zerrin Ruins

As An-Zerrin Ruins enters, choose a creature type.
Creatures of the chosen type don't untap during their controllers' untap steps.