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.

Diabolic Tutor

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

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.

Bottomless Pit

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

Burglar Rat

When Burglar Rat enters the battlefield, each opponent discards a card.

Tergrid's Lantern

{T}: Target player loses 3 life unless they sacrifice a nonland permanent 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

Dread Presence

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

Jet Medallion

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

Grave Pact

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

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

Wit's End

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Hero's Downfall

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature.

Damnable Pact

Target player draws X cards and loses X life.

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.

Painful Quandary

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

Tourach, Dread Cantor

Kicker {B}{B} (You may pay an additional {B}{B} as you cast this spell.)
Protection from white
Whenever an opponent discards a card, put a +1/+1 counter on Tourach, Dread Cantor.
When Tourach enters the battlefield, if it was kicked, target opponent discards two cards at random.

Nirkana Revenant

Whenever you tap a Swamp for mana, add an additional {B}.
{B}: Nirkana Revenant gets +1/+1 until end of turn.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker and gets a poison counter.

The Cruelty of Gix

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.
II — Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.
III — Put target creature card from a graveyard onto the battlefield under your control.

Ill-Gotten Gains

Exile Ill-Gotten Gains. Each player discards their hand, then returns up to three cards from their graveyard to their hand.

Sol Ring

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth, Spider Queen.
0: You draw a card and you lose 1 life.
−3: Create two 2/1 black Spider creature tokens with menace and reach.
−8: You get an emblem with "Whenever an opponent is dealt combat damage by one or more creatures you control, if that player lost less than 8 life this turn, they lose life equal to the difference."

Hypnotic Specter

Flying
Whenever Hypnotic Specter deals damage to an opponent, that player discards a card at random.

Necrogen Mists

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

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Archfiend of Despair

Flying
Your opponents can't gain life.
At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

Oppression

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

Anvil of Bogardan

Players have no maximum hand size.
At the beginning of each player's draw step, that player draws an additional card, then discards a card.

Nezumi Informant

When Nezumi Informant enters the battlefield, each opponent discards a card.

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Nefarox, Overlord of Grixis

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever Nefarox, Overlord of Grixis attacks alone, defending player sacrifices a creature.

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.

Cunning Lethemancer

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

Geier Reach Sanitarium

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

Grief

Menace
When Grief enters the battlefield, target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Evoke—Exile a black card from your hand.

Geth's Grimoire

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

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."

Sheoldred's Edict

Choose one —
• Each opponent sacrifices a nontoken creature.
• Each opponent sacrifices a creature token.
• Each opponent sacrifices a planeswalker.

Cruel Edict

Exsanguinate

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

Cursed Rack

As Cursed Rack enters the battlefield, choose an opponent.
The chosen player's maximum hand size is four.

Defiler of Flesh

Menace
As an additional cost to cast black permanent spells, you may pay 2 life. Those spells cost {B} less to cast if you paid life this way. This effect reduces only the amount of black mana you pay.
Whenever you cast a black permanent spell, target creature you control gets +1/+1 and gains menace until end of turn.

Wishclaw Talisman

Wishclaw Talisman enters the battlefield with three wish counters on it.
{1}, {T}, Remove a wish counter from Wishclaw Talisman: Search your library for a card, put it into your hand, then shuffle. An opponent gains control of Wishclaw Talisman. Activate only during your turn.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Okiba-Gang Shinobi

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Okiba-Gang Shinobi deals combat damage to a player, that player discards two cards.

Liliana of the Veil

+1: Each player discards a card.
−2: Target player sacrifices a creature.
−6: Separate all permanents target player controls into two piles. That player sacrifices all permanents in the pile of their choice.

Rankle's Prank

Choose one or more —
• Each player discards two cards.
• Each player loses 4 life.
• Each player sacrifices two creatures.

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.

Dark Ritual

Seizan, Perverter of Truth

At the beginning of each player's upkeep, that player loses 2 life and draws two cards.

Professor Onyx

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life.
+1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
−3: Each opponent sacrifices a creature with the greatest power among creatures that player controls.
−8: Each opponent may discard a card. If they don't, they lose 3 life. Repeat this process six more times.

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}.

Arcane Signet

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

Shrieking Affliction

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 3 life.

Phyrexian Arena

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

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Temple of the Dead

(Transforms from Aclazotz, Deepest Betrayal.)
{T}: Add {B}.
{2}{B}, {T}: Transform Temple of the Dead. Activate only if a player has one or fewer cards in hand and only as a sorcery.

Aclazotz, Deepest Betrayal

Flying, lifelink
Whenever Aclazotz attacks, each opponent discards a card. For each opponent who can't, you draw a card.
Whenever an opponent discards a land card, create a 1/1 black Bat creature token with flying.
When Aclazotz dies, return it to the battlefield tapped and transformed under its owner's control.

Aclazotz, Deepest Betrayal // Temple of the Dead

Mind Twist

Target player discards X cards at random.

Tinybones, Trinket Thief

At the beginning of each end step, if an opponent discarded a card this turn, you draw a card and you lose 1 life.
{4}{B}{B}: Each opponent with no cards in hand loses 10 life.

Archon of Cruelty

Flying
Whenever Archon of Cruelty enters the battlefield or attacks, target opponent sacrifices a creature or planeswalker, discards a card, and loses 3 life. You draw a card and gain 3 life.