Demonic Tutor

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

Have

Tinybones, Bauble Burglar

Whenever an opponent discards a card, exile it from their graveyard with a stash counter on it.
During your turn, you may play cards you don't own with stash counters on them from exile, and mana of any type can be spent to cast those spells.
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Painful Quandary

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

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.)

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.

Tinybones, the Pickpocket

Deathtouch
Whenever Tinybones deals combat damage to a player, you may cast target nonland permanent card from that player's graveyard, and mana of any type can be spent to cast that spell.

Liliana, Waker of the Dead

+1: Each player discards a card. Each opponent who can't loses 3 life.
−3: Target creature gets -X/-X until end of turn, where X is the number of cards in your graveyard.
−7: You get an emblem with "At the beginning of combat on your turn, put target creature card from a graveyard onto the battlefield under your control. It gains haste."

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}.

The Raven Man

At the beginning of each end step, if a player discarded a card this turn, create a 1/1 black Bird creature token with flying and "This token can't block."
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Sol Ring

Mindslicer

When this creature dies, each player discards their hand.

Cunning Lethemancer

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

Sudden Spoiling

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

Braids's Frightful Return

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 — You may sacrifice a creature. If you do, each opponent discards a card.
II — Return target creature card from your graveyard to your hand.
III — Target opponent may sacrifice a nonland, nontoken permanent of their choice. If they don't, they lose 2 life and you draw a card.

Oppression

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

Malakir Mire

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Mind Stone

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

Megrim

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

Junji, the Midnight Sky

Flying, menace
When Junji dies, choose one —
• Each opponent discards two cards and loses 2 life.
• Put target non-Dragon creature card from a graveyard onto the battlefield under your control. You lose 2 life.

Arterial Flow

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

Delirium Skeins

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.

Hopeless Nightmare

When this enchantment enters, each opponent discards a card and loses 2 life.
When this enchantment is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice this enchantment.

Hostile Investigator

When this creature enters, target opponent discards a card.
Whenever one or more players discard one or more cards, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

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

Damnation

Destroy all creatures. They can't be regenerated.

Vicious Rumors

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

Cabal Coffers

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

Jet Medallion

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

Toxic Deluge

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

Forsaken Wastes

Players can't gain life.
At the beginning of each player's upkeep, that player loses 1 life.
Whenever this enchantment becomes the target of a spell, that spell's controller loses 5 life.

Arcane Signet

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

Liliana's Caress

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

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Liliana of the Dark Realms

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
−3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.
−6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

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.

Archon of Cruelty

Flying
Whenever this creature enters or attacks, target opponent sacrifices a creature or planeswalker of their choice, discards a card, and loses 3 life. You draw a card and gain 3 life.

Phyrexian Arena

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

Bandit's Talent

(Gain the next level as a sorcery to add its ability.)
When this Class enters, each opponent discards two cards unless they discard a nonland card.
{B}: Level 2
At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 2 life.
{3}{B}: Level 3
At the beginning of your draw step, draw an additional card for each opponent who has one or fewer cards in hand.

Witch's Cottage

({T}: Add {B}.)
This land enters tapped unless you control three or more other Swamps.
When this land enters untapped, you may put target creature card from your graveyard on top of your library.

Geier Reach Sanitarium

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

Tinybones Joins Up

When Tinybones Joins Up enters, any number of target players each discard a card.
Whenever a legendary creature you control enters, any number of target players each mill a card and lose 1 life.

Burglar Rat

When this creature enters, each opponent discards a card.

Boggart Bog

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

Boggart Trawler

When this creature enters, exile target player's graveyard.

Boggart Trawler // Boggart Bog

Torment of Hailfire

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

Barren Moor

This land enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Geth's Grimoire

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

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.

Blasphemous Edict

You may pay {B} rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield.
Each player sacrifices thirteen creatures of their choice.

Thought Vessel

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

Dark Deal

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

Go for the Throat

Consuming Corruption

Consuming Corruption deals X damage to target creature or planeswalker and you gain X life, where X is the number of Swamps you control.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Liliana's Specter

Flying
When this creature enters, each opponent discards a card.

Pilfer

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Bird

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Night's Whisper

Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Necrogen Mists

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

Gonti, Night Minister

Whenever a player casts a spell they don't own, that player creates a Treasure token.
Whenever a creature deals combat damage to one of your opponents, its controller looks at the top card of that opponent's library and exiles it face down. They may play that card for as long as it remains exiled. Mana of any type can be spent to cast a spell this way.

Temple of the Dead

(Transforms from Aclazotz, Deepest Betrayal.)
{T}: Add {B}.
{2}{B}, {T}: Transform this land. 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

Dark Ritual

War Room

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

Rankle, Master of Pranks

Flying, haste
Whenever Rankle 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.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Swamp

Nezumi Informant

Imp's Mischief

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

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Urborg, Tomb of Yawgmoth

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

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.

Zombie

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.
When Tourach enters, if it was kicked, target opponent discards two cards at random.