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.

Brain Weevil

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Sacrifice Brain Weevil: Target player discards two cards. Activate only as a sorcery.

Bloodtithe Collector

Flying
When Bloodtithe Collector enters the battlefield, if an opponent lost life this turn, each opponent discards a card.

Oblivion

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Target opponent discards two cards.

Consign

Return target nonland permanent to its owner's hand.

Consign // Oblivion

Cabal Conditioning

Any number of target players each discard a number of cards equal to the highest mana value among permanents you control.

Corrupt Court Official

When Corrupt Court Official enters the battlefield, target opponent discards a card.

Chain of Smog

Target player discards two cards. That player may copy this spell and may choose a new target for that copy.

Coral Net

Enchant green or white creature
Enchanted creature has "At the beginning of your upkeep, sacrifice this creature unless you discard a card."

Chilling Apparition

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

Brutal Nightstalker

When Brutal Nightstalker enters the battlefield, you may have target opponent discard a card.

Cinderhaze Wretch

{T}: Target player discards a card. Activate only during your turn.
Put a -1/-1 counter on Cinderhaze Wretch: Untap Cinderhaze Wretch.

Cryptwailing

{1}, Exile two creature cards from your graveyard: Target player discards a card. Activate only as a sorcery.

Awaken the Erstwhile

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

Brain Pry

Choose a nonland card name. Target player reveals their hand. That player discards a card with that name. If they can't, you draw a card.

Alley Grifters

Whenever Alley Grifters becomes blocked, defending player discards a card.

Amnesia

Target player reveals their hand and discards all nonland cards.

Breathstealer's Crypt

If a player would draw a card, instead they draw a card and reveal it. If it's a creature card, that player discards it unless they pay 3 life.

Banshee of the Dread Choir

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token that's a copy of this creature 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.

Cao Cao, Lord of Wei

{T}: Target opponent discards two cards. Activate only during your turn, before attackers are declared.

Augur of Skulls

{1}{B}: Regenerate Augur of Skulls.
Sacrifice Augur of Skulls: Target player discards two cards. Activate only during your upkeep.

Bad Deal

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

Carnage

Carnage deals 3 damage to target opponent. That player discards two cards.

Carnival

Carnival deals 1 damage to target creature or planeswalker and 1 damage to that permanent's controller.

Carnival // Carnage

Abandon Hope

As an additional cost to cast this spell, discard X cards.
Look at target opponent's hand and choose X cards from it. That player discards those cards.

Brink of Madness

At the beginning of your upkeep, if you have no cards in hand, sacrifice Brink of Madness and target opponent discards their hand.

Abyssal Nocturnus

Whenever an opponent discards a card, Abyssal Nocturnus gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Arterial Flow

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

Caligo Skin-Witch

Kicker {3}{B} (You may pay an additional {3}{B} as you cast this spell.)
When Caligo Skin-Witch enters the battlefield, if it was kicked, each opponent discards two cards.

Coercion

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

Aspect of Lamprey

Enchant creature you control
When Aspect of Lamprey enters the battlefield, target opponent discards two cards.
Enchanted creature has lifelink.

Aggressive Sabotage

Kicker {R} (You may pay an additional {R} as you cast this spell.)
Target player discards two cards. If this spell was kicked, it deals 3 damage to that player.

Burglar Rat

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

Blizzard Specter

Flying
Whenever Blizzard Specter deals combat damage to a player, choose one —
• That player returns a permanent they control to its owner's hand.
• That player discards a card.

Blazing Specter

Flying, haste
Whenever Blazing Specter deals combat damage to a player, that player discards a card.

Cackling Fiend

When Cackling Fiend enters the battlefield, each opponent discards a card.

Cabal Inquisitor

Threshold — {1}{B}, {T}, Exile two cards from your graveyard: Target player discards a card. Activate only as a sorcery and only if seven or more cards are in your graveyard.

Blackmail

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

Cabal Interrogator

{X}{B}, {T}: Target player reveals X cards from their hand and you choose one of them. That player discards that card. Activate only as a sorcery.

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.

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.

Consult the Necrosages

Choose one —
• Target player draws two cards.
• Target player discards two cards.

Barbed Shocker

Trample, haste
Whenever Barbed Shocker deals damage to a player, that player discards all the cards in their hand, then draws that many cards.

Cat Burglar

{2}{B}, {T}: Target player discards a card. Activate only as a sorcery.

Bala Ged Thief

Whenever Bala Ged Thief or another Ally enters the battlefield under your control, target player reveals a number of cards from their hand equal to the number of Allies you control. You choose one of them. That player discards that card.

Chain of Plasma

Chain of Plasma deals 3 damage to any target. Then that player or that permanent's controller may discard a card. If the player does, they may copy this spell and may choose a new target for that copy.

Abyssal Nightstalker

Whenever Abyssal Nightstalker attacks and isn't blocked, defending player discards a card.

Corrupt Official

{2}{B}: Regenerate Corrupt Official.
Whenever Corrupt Official becomes blocked, defending player discards a card at random.

Crosis, the Purger

Flying
Whenever Crosis, the Purger deals combat damage to a player, you may pay {2}{B}. If you do, choose a color, then that player reveals their hand and discards all cards of that color.

Apathy

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player may discard a card at random. If the player does, untap that creature.

Angrath, the Flame-Chained

+1: Each opponent discards a card and loses 2 life.
−3: Gain control of target creature until end of turn. Untap it. It gains haste until end of turn. Sacrifice it at the beginning of the next end step if it has mana value 3 or less.
−8: Each opponent loses life equal to the number of cards in their graveyard.

Addle

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

Black Cat

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

Bereavement

Whenever a green creature dies, its controller discards a card.

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. If they don't, they lose 2 life and you draw a card.

Cruel Grimnarch

Deathtouch
When Cruel Grimnarch enters the battlefield, each opponent discards a card. For each opponent who can't, you gain 4 life.

Cloak of Confusion

Enchant creature you control
Whenever enchanted creature attacks and isn't blocked, you may have it assign no combat damage this turn. If you do, defending player discards a card at random.

Court of Ambition

When Court of Ambition enters the battlefield, 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.

Abyssal Specter

Flying
Whenever Abyssal Specter deals damage to a player, that player discards a card.