Gibbering Descent

At the beginning of each player's upkeep, that player loses 1 life and discards a card.
Hellbent — Skip your upkeep step if you have no cards in hand.
Madness {2}{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.)

Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Cackling Fiend

When Cackling Fiend enters, each opponent discards a card.

Needle Specter

Flying
Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever Needle Specter deals combat damage to a player, that player discards that many cards.

Rotting Rats

When Rotting Rats enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Bloodhusk Ritualist

Multikicker {B} (You may pay an additional {B} any number of times as you cast this spell.)
When Bloodhusk Ritualist enters, target opponent discards a card for each time it was kicked.

Shrieking Specter

Flying
Whenever Shrieking Specter attacks, defending player discards a card.

Stabwhisker the Odious

At the beginning of each opponent's upkeep, that player loses 1 life for each card fewer than three in their hand.

Nezumi Shortfang

{1}{B}, {T}: Target opponent discards a card. Then if that player has no cards in hand, flip Nezumi Shortfang.

Nezumi Shortfang // Stabwhisker the Odious

Abyssal Specter

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

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.

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.

Specter's Shroud

Equipped creature gets +1/+0.
Whenever equipped creature deals combat damage to a player, that player discards a card.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)

Silent Specter

Flying
Whenever Silent Specter deals combat damage to a player, that player discards two cards.
Morph {3}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

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.)

Guul Draz Specter

Flying
Guul Draz Specter gets +3/+3 as long as an opponent has no cards in hand.
Whenever Guul Draz Specter deals combat damage to a player, that player discards a card.

Ashen-Skin Zubera

When Ashen-Skin Zubera dies, target opponent discards a card for each Zubera that died this turn.

Bottomless Pit

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

Nihilistic Glee

{2}{B}, Discard a card: Target opponent loses 1 life and you gain 1 life.
Hellbent — {1}, Pay 2 life: Draw a card. Activate only if you have no cards in hand.

Augur of Skulls

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

Cunning Lethemancer

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

Liliana, the Last Hope

+1: Up to one target creature gets -2/-1 until your next turn.
−2: Mill two cards, then you may return a creature card from your graveyard to your hand.
−7: You get an emblem with "At the beginning of your end step, create X 2/2 black Zombie creature tokens, where X is two plus the number of Zombies you control."

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.

Necrogen Mists

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

Dying Wail

Enchant creature
When enchanted creature dies, target player discards two cards.

Mindlash Sliver

All Slivers have "{1}, Sacrifice this permanent: Each player discards a card."

Geth's Grimoire

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

Hypnotic Specter

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

Liliana's Caress

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

Corrupt Court Official

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

Exiled Boggart

When Exiled Boggart dies, discard a card.

Words of Waste

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

Cao Cao, Lord of Wei

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

Megrim

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

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Dauthi Mindripper

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Dauthi Mindripper attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards.

Oppression

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

Liliana, Defiant Necromancer

+2: Each player discards a card.
−X: Return target nonlegendary creature card with mana value X from your graveyard to the battlefield.
−8: You get an emblem with "Whenever a creature dies, return it to the battlefield under your control at the beginning of the next end step."

Liliana, Heretical Healer

Lifelink
Whenever another nontoken creature you control dies, exile Liliana, Heretical Healer, then return her to the battlefield transformed under her owner's control. If you do, create a 2/2 black Zombie creature token.

Liliana, Heretical Healer // Liliana, Defiant Necromancer

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.

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.

Cunning Advisor

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

Shimian Specter

Flying
Whenever Shimian Specter deals combat damage to a player, that player reveals their hand. You choose a nonland card from it. Search that player's graveyard, hand, and library for all cards with the same name as that card and exile them. Then that player shuffles.

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}.'"

Painful Quandary

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