Bottomless Pit

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

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, if it was kicked, target opponent discards two cards at random.

Duress

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

Hex Parasite

{X}{B/P}: Remove up to X counters from target permanent. For each counter removed this way, Hex Parasite gets +1/+0 until end of turn. ({B/P} can be paid with either {B} or 2 life.)

Virus Beetle

When Virus Beetle enters, each opponent discards a card.

Swamp

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{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.)

Augur of Skulls

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

Blackmail

Target player reveals three cards from their hand and you choose one of them. 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.

Disruptor Flute

Flash
As Disruptor Flute enters, choose a card name.
Spells with the chosen name cost {3} more to cast.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Bandit's Talent

(Gain the next level as a sorcery to add its ability.)
When Bandit's Talent enters, each opponent discards two cards unless they discard a nonland card.
{B}: Level 2
At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 2 life.
{3}{B}: Level 3
At the beginning of your draw step, draw an additional card for each opponent who has one or fewer cards in hand.

Syphon Mind

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

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Spectral Snatcher

Ward—Discard a card. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player discards a card.)
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Shrieking Affliction

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

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Let's Play a Game

Delirium — Choose one. If there are four or more card types among cards in your graveyard, choose one or more instead.
• Creatures your opponents control get -1/-1 until end of turn.
• Each opponent discards two cards.
• Each opponent loses 3 life and you gain 3 life.

Osseous Sticktwister

Lifelink
Delirium — At the beginning of your end step, if there are four or more card types among cards in your graveyard, each opponent may sacrifice a nonland permanent of their choice or discard a card. Then Osseous Sticktwister deals damage equal to its power to each opponent who didn't sacrifice a permanent or discard a card this way.

Tinybones Joins Up

When Tinybones Joins Up enters, any number of target players each discard a card.
Whenever a legendary creature you control enters, any number of target players each mill a card and lose 1 life.

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.)

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."

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

The Elderspell

Destroy any number of target planeswalkers. Choose a planeswalker you control. Put two loyalty counters on it for each planeswalker destroyed this way.

Fell Specter

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

Smallpox

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

Vicious Rumors

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

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Vampire Hexmage

First strike
Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Cunning Lethemancer

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

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Nezumi Informant

When Nezumi Informant enters, each opponent discards a card.

Painful Quandary

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

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.

Megrim

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

Elderfang Disciple

When Elderfang Disciple enters, each opponent discards a card.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Geth's Grimoire

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

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.