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.

Court of Ambition

When Court of Ambition enters, 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.

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

Greel, Mind Raker

{X}{B}, {T}, Discard two cards: Target player discards X cards at random.

Shrieking Affliction

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

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

Vicious Rumors

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

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Deadly Rollick

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

Cunning Lethemancer

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

Cabal Stronghold

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

Hypnotic Specter

Flying
Whenever Hypnotic Specter deals damage to an opponent, that player 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.

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.

Megrim

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

Delirium Skeins

Dark Ritual

Cabal Coffers

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

Fell Specter

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

Wheel of Torture

At the beginning of each opponent's upkeep, Wheel of Torture deals X damage to that player, where X is 3 minus the number of cards in their hand.

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.)

Arterial Flow

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

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.

Liliana's Caress

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

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.

Mindlash Sliver

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

Funeral Charm

Choose one —
• Target player discards a card.
• Target creature gets +2/-1 until end of turn.
• Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)

Swamp

Bottomless Pit

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

Elderfang Disciple

When Elderfang Disciple enters, each opponent discards a card.

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.

Syphon Mind

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

Massacre Wurm

When Massacre Wurm enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.