Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Soul Shatter

Each opponent sacrifices a creature or planeswalker with the highest mana value among creatures and planeswalkers they control.

Mind Rake

Target player discards two cards.
Overload {1}{B} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

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.

Charcoal Diamond

This artifact enters tapped.
{T}: Add {B}.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Court of Ambition

When this enchantment 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.

Star Compass

This artifact enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Barter in Blood

Each player sacrifices two creatures of their choice.

Merciless Executioner

When this creature enters, each player sacrifices a creature of their choice.

Delirium Skeins

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Sol Ring

Arterial Flow

Each opponent discards two cards. If you control a Vampire, each opponent loses 2 life and you gain 2 life.

Vicious Rumors

Vicious Rumors deals 1 damage to each opponent. Each opponent discards a card, then mills a card. You gain 1 life.

Elderfang Disciple

When this creature enters, each opponent discards a card.

Desolation

At the beginning of each end step, each player who tapped a land for mana this turn sacrifices a land of their choice. This enchantment deals 2 damage to each player who sacrificed a Plains this way.

Rotting Rats

When this creature enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Demon's Disciple

When this creature enters, each player sacrifices a creature or planeswalker of their choice.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Awaken the Erstwhile

Each player discards all the cards in their hand, then creates that many 2/2 black Zombie creature tokens.

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Plaguecrafter

When this creature enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Oppression

Whenever a player casts a spell, that player discards a card.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Mindslicer

When this creature dies, each player discards their hand.

Cunning Lethemancer

At the beginning of your upkeep, each player discards a card.

Elvish Doomsayer

When this creature dies, each opponent discards a card.

Sign in Blood

Target player draws two cards and loses 2 life.

Fell Specter

Flying
When this creature enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Capital Punishment

Council's dilemma — Starting with you, each player votes for death or taxes. Each opponent sacrifices a creature of their choice for each death vote and discards a card for each taxes vote.

Fraying Omnipotence

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the creatures they control of their choice. Round up each time.

Burglar Rat

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Innocent Blood

Each player sacrifices a creature of their choice.

Duress

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

Diabolic Edict

Target player sacrifices a creature of their choice.

Gilded Lotus

Bottomless Pit

At the beginning of each player's upkeep, that player discards a card at random.

Tergrid's Lantern

{T}: Target player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.
{3}{B}: Untap Tergrid's Lantern.

Tergrid, God of Fright

Menace
Whenever an opponent sacrifices a nontoken permanent or discards a permanent card, you may put that card from a graveyard onto the battlefield under your control.

Tergrid, God of Fright // Tergrid's Lantern

Geth's Grimoire

Whenever an opponent discards a card, you may draw a card.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature of their choice, then sacrifices a land of their choice.

Liliana's Triumph

Each opponent sacrifices a creature of their choice. If you control a Liliana planeswalker, each opponent also discards a card.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
This artifact enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on this artifact.

Each player loses a third of their life, then discards a third of the cards in their hand, then sacrifices a third of the creatures they control of their choice, then sacrifices a third of the lands they control of their choice. Round up each time.

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Mire in Misery

Each opponent sacrifices a creature or enchantment of their choice.

Go for the Throat

Hymn to Tourach

Target player discards two cards at random.

Swamp

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Fleshbag Marauder

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Dark Deal

Each player discards all the cards in their hand, then draws that many cards minus one.