Hopeless Nightmare

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

Liliana's Caress

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

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.

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."

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 creature can't block."
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Take It Back

Return target spell to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Spellscorn Coven

Flying
When Spellscorn Coven enters the battlefield, each opponent discards a card.

Spellscorn Coven // Take It Back

Vindictive Lich

When Vindictive Lich dies, choose one or more. Each mode must target a different player.
• Target opponent sacrifices a creature.
• Target opponent discards two cards.
• Target opponent loses 5 life.

Tasigur's Cruelty

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Each opponent discards two cards.

Nezumi Informant

When Nezumi Informant enters the battlefield, each opponent discards a card.

Skull Rend

Skull Rend deals 2 damage to each opponent. Those players each discard two cards at random.

Lazotep Convert

You may have Lazotep Convert enter the battlefield as a copy of any creature card in a graveyard, except it's a 4/4 black Zombie in addition to its other colors and types.

Invasion of Amonkhet

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Amonkhet enters the battlefield, each player mills three cards, then each opponent discards a card and you draw a card. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Invasion of Amonkhet // Lazotep Convert

Arterial Flow

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

Cruel Grimnarch

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

Basilica Bell-Haunt

When Basilica Bell-Haunt enters the battlefield, each opponent discards a card and you gain 3 life.

The Eldest Reborn

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent sacrifices a creature or planeswalker.
II — Each opponent discards a card.
III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.

Burglar Rat

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

Elvish Doomsayer

When Elvish Doomsayer dies, each opponent discards a card.

Dream Salvage

Draw cards equal to the number of cards target opponent discarded this turn.

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.

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.

Bad Deal

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

Torment of Hailfire

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

Vicious Rumors

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

Unnerve

Bladecoil Serpent

When Bladecoil Serpent enters the battlefield, for each {U}{U} spent to cast it, draw a card.
When Bladecoil Serpent enters the battlefield, for each {B}{B} spent to cast it, each opponent discards a card.
When Bladecoil Serpent enters the battlefield, for each {R}{R} spent to cast it, it gets +1/+0 and gains trample and haste until end of turn.

Enemy of Enlightenment

Flying
Enemy of Enlightenment gets -1/-1 for each card in your opponents' hands.
At the beginning of your upkeep, each player discards a card.

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

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.

Virus Beetle

When Virus Beetle enters the battlefield, each opponent discards a card.

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.

Daemogoth Woe-Eater

At the beginning of your upkeep, sacrifice a creature.
When you sacrifice Daemogoth Woe-Eater, each opponent discards a card, you draw a card, and you gain 2 life.