Cry of Contrition

Target player discards a card.
Haunt (When this spell card is put into a graveyard after resolving, exile it haunting target creature.)
When the creature Cry of Contrition haunts dies, target player discards a card.

Ostracize

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

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.

Life's Finale

Destroy all creatures, then search target opponent's library for up to three creature cards and put them into their graveyard. Then that player shuffles.

Palace Siege

As Palace Siege enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, return target creature card from your graveyard to your hand.
• Dragons — At the beginning of your upkeep, each opponent loses 2 life and you gain 2 life.

Syphon Mind

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

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Warped Devotion

Whenever a permanent is returned to a player's hand, that player discards a card.

Mental Vapors

Target player discards a card.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Quest for the Nihil Stone

Whenever an opponent discards a card, you may put a quest counter on Quest for the Nihil Stone.
At the beginning of each opponent's upkeep, if that player has no cards in hand and Quest for the Nihil Stone has two or more quest counters on it, you may have that player lose 5 life.

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.

Chains of Mephistopheles

If a player would draw a card except the first one they draw in each of their draw steps, that player discards a card instead. If the player discards a card this way, they draw a card. If the player doesn't discard a card this way, they mill a card.

Megrim

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

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.

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.

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

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.

Bottomless Pit

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

Entomber Exarch

When Entomber Exarch enters, choose one —
• Return target creature card from your graveyard to your hand.
• Target opponent reveals their hand. You choose a noncreature card from it. That player discards that card.

Urborg Stalker

At the beginning of each player's upkeep, if that player controls a nonblack, nonland permanent, Urborg Stalker deals 1 damage to that player.

Creeping Dread

At the beginning of your upkeep, each player discards a card. Each opponent who discarded a card that shares a card type with the card you discarded loses 3 life. (Players reveal the discarded cards simultaneously.)

Geth's Grimoire

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

Teferi's Puzzle Box

At the beginning of each player's draw step, that player puts the cards in their hand on the bottom of their library in any order, then draws that many cards.

Smallpox

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

Davriel, Rogue Shadowmage

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, Davriel, Rogue Shadowmage deals 2 damage to them.
−1: Target player discards a card.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel 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.)

Midnight Banshee

Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.

Larceny

Whenever a creature you control deals combat damage to a player, that player discards a card.

Death Cloud

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

Herald of Anguish

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Filth

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
As long as Filth is in your graveyard and you control a Swamp, creatures you control have swampwalk.

Blackmail

Target player reveals three cards from their hand and you choose one of them. That player discards that card.

Mire's Toll

Target player reveals a number of cards from their hand equal to the number of Swamps you control. You choose one of them. That player discards that card.

Distress

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

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.")

Bone Miser

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

Memory Jar

{T}, Sacrifice Memory Jar: Each player exiles all cards from their hand face down and draws seven cards. At the beginning of the next end step, each player discards their hand and returns to their hand each card they exiled this way.

Hypnotic Specter

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

Burglar Rat

When this creature enters, each opponent discards a card.

Drill Bit

Spectacle {B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Cunning Lethemancer

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

Delirium Skeins

Mindwarper

Mindwarper enters with three +1/+1 counters on it.
{2}{B}, Remove a +1/+1 counter from Mindwarper: Target player discards a card. Activate only as a sorcery.

Geth, Lord of the Vault

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{X}{B}: Put target artifact or creature card with mana value X from an opponent's graveyard onto the battlefield under your control tapped. Then that player mills X cards.

Oppression

Whenever a player casts a spell, that player discards 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.

Liliana's Caress

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

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.

The Haunt of Hightower

Flying, lifelink
Whenever The Haunt of Hightower attacks, defending player discards a card.
Whenever a card is put into an opponent's graveyard from anywhere, put a +1/+1 counter on The Haunt of Hightower.

Bad Deal

You draw two cards and each opponent discards two cards. Each player loses 2 life.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Hollow Specter

Flying
Whenever Hollow Specter deals combat damage to a player, you may pay {X}. If you do, that player reveals X cards from their hand and you choose one of them. That player discards that card.

Banshee of the Dread Choir

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Banshee of the Dread Choir deals combat damage to a player, that player discards a card.

Words of Waste

{1}: The next time you would draw a card this turn, each opponent discards a card instead.

Urgoros, the Empty One

Flying
Whenever Urgoros, the Empty One deals combat damage to a player, that player discards a card at random. If the player can't, you draw a card.

Vow of Malice

Enchant creature
Enchanted creature gets +2/+2, has intimidate, and can't attack you or planeswalkers you control. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Duress

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

Monomania

Target player chooses a card in their hand and discards the rest.

Unnerve

Vicious Rumors

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

Swamp

Mindslicer

When Mindslicer dies, each player discards their hand.

Addle

Choose a color. Target player reveals their hand and you choose a card of that color from it. That player discards that card.

Chilling Apparition

{B}: Regenerate Chilling Apparition.
Whenever Chilling Apparition deals combat damage to a player, 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.

Noxious Vapors

Each player reveals their hand, chooses one card of each color from it, then discards all other nonland cards.

Black Cat

When Black Cat dies, target opponent discards a card at random.

Raiders' Wake

Whenever an opponent discards a card, that player loses 2 life.
Raid — At the beginning of your end step, if you attacked this turn, target opponent discards a card.

Fell Specter

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

Pulling Teeth

Clash with an opponent. If you win, target player discards two cards. Otherwise, that player discards a card. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Urborg, Tomb of Yawgmoth

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

Painful Quandary

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

Earsplitting Rats

When Earsplitting Rats enters, each player discards a card.
Discard a card: Regenerate Earsplitting Rats.