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.

Hagra Broodpit

Hagra Broodpit enters tapped.
{T}: Add {B}.

Hagra Mauling

This spell costs {1} less to cast if an opponent controls no basic lands.
Destroy target creature.

Hagra Mauling // Hagra Broodpit

Jet Medallion

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

Innocent Blood

Each player sacrifices a creature of their choice.

Smallpox

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

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Diabolic Tutor

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

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

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.

Have

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

Dark Deal

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

Skull Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game.
Each opponent sacrifices a creature of their choice. Each opponent who can't loses half their life, rounded up.

Waste Not

Whenever an opponent discards a creature card, create a 2/2 black Zombie creature token.
Whenever an opponent discards a land card, add {B}{B}.
Whenever an opponent discards a noncreature, nonland card, draw a card.

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Mind Slash

{B}, Sacrifice a creature: Target opponent reveals their hand. You choose a card from it. That player discards that card. Activate only as a sorcery.

Chainer's Edict

Target player sacrifices a creature of their choice.
Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Cabal Coffers

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

Killing Wave

For each creature, its controller sacrifices it unless they pay X life.

Desolation

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

Bitterblossom

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

Szat's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Each opponent sacrifices a creature they control with the greatest power.
• Exile all opponents' graveyards, then create X 0/1 black Thrull creature tokens, where X is the greatest power among creature cards exiled this way.

Merciless Executioner

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

Death Cloud

Each player loses X life, discards X cards, sacrifices X creatures of their choice, then sacrifices X lands of their choice.

Mire in Misery

Each opponent sacrifices a creature or enchantment of their choice.

Dead of Winter

All nonsnow creatures get -X/-X until end of turn, where X is the number of snow permanents you control.

Raven's Crime

Target player discards a card.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Toxic Deluge

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

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Sheoldred, Whispering One

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature of their choice.

Demon's Disciple

When Demon's Disciple enters, each player sacrifices a creature or planeswalker of their choice.

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.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Myojin of Night's Reach

Myojin of Night's Reach enters with a divinity counter on it if you cast it from your hand.
Myojin of Night's Reach has indestructible as long as it has a divinity counter on it.
Remove a divinity counter from Myojin of Night's Reach: Each opponent discards their hand.

Consuming Vapors

Target player sacrifices a creature of their choice. You gain life equal to that creature's toughness.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Snow-Covered Swamp

Bubbling Muck

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

Erebos, God of the Dead

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Your opponents can't gain life.
{1}{B}, Pay 2 life: Draw a card.

Dreamstealer

Menace
Whenever Dreamstealer deals combat damage to a player, that player discards that many cards.
Eternalize {4}{B}{B} ({4}{B}{B}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Human Wizard with no mana cost. Eternalize only as a sorcery.)

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Rankle, Master of Pranks

Flying, haste
Whenever Rankle, Master of Pranks deals combat damage to a player, choose any number —
• Each player discards a card.
• Each player loses 1 life and draws a card.
• Each player sacrifices a creature of their choice.

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.)

Choice of Damnations

Target opponent chooses a number. You may have that player lose that much life. If you don't, that player sacrifices all but that many permanents of their choice.

Burglar Rat

When this creature enters, each opponent discards a card.

Dread Presence

Whenever a Swamp you control enters, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Vona's Hunger

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Each opponent sacrifices a creature of their choice. If you have the city's blessing, instead each opponent sacrifices half the creatures they control of their choice, rounded up.

Geier Reach Sanitarium

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

Agadeem, the Undercrypt

As Agadeem, the Undercrypt enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Agadeem's Awakening

Return from your graveyard to the battlefield any number of target creature cards that each have a different mana value X or less.