Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Addle

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

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.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Asylum Visitor

At the beginning of each player's upkeep, if that player has no cards in hand, you draw a card and you lose 1 life.
Madness {1}{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.)

Coercion

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

Dreamstealer

Menace
Whenever Dreamstealer deals combat damage to a player, that player discards that many cards.
Eternalize {4}{B}{B} ({4}{B}{B}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Human Wizard with no mana cost. Eternalize only as a sorcery.)

Elvish Doomsayer

When Elvish Doomsayer dies, each opponent discards a card.

Merciless Executioner

When Merciless Executioner enters, each player sacrifices a creature of their choice.

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Dark Ritual

Underworld Connections

Enchant land
Enchanted land has "{T}, Pay 1 life: Draw a card."

Cabal Conditioning

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

Syphon Mind

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

Greed

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Delirium Skeins

Miasmic Mummy

When Miasmic Mummy enters, each player discards a card.

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

Arterial Flow

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

Megrim

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

Blood Pact

Target player draws two cards and loses 2 life.

Ancient Craving

You draw three cards and you lose 3 life.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Liliana's Triumph

Each opponent sacrifices a creature of their choice. If you control a Liliana planeswalker, each opponent also discards a card.

Burglar Rat

When this creature enters, each opponent discards a card.

Abyssal Specter

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

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.

Duress

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

Demon's Disciple

When Demon's Disciple enters, each player sacrifices a creature or planeswalker of their choice.

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.

Demogorgon's Clutches

Target opponent discards two cards, mills two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Awaken the Erstwhile

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

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Elderfang Disciple

When Elderfang Disciple enters, each opponent discards a card.

Sol Ring

Cinderhaze Wretch

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

Bog Down

Kicker—Sacrifice two lands. (You may sacrifice two lands in addition to any other costs as you cast this spell.)
Target player discards two cards. If this spell was kicked, that player discards three cards instead.

Plaguecrafter

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

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Innocent Blood

Each player sacrifices a creature of their choice.

Sign in Blood

Barter in Blood

Each player sacrifices two creatures of their choice.

Ambition's Cost

Swamp

Mire in Misery

Each opponent sacrifices a creature or enchantment of their choice.

Mind Shatter

Target player discards X cards at random.

Fraying Omnipotence

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the creatures they control of their choice. Round up each time.

Despise

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

Leaden Myr

Blackmail

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

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Guardian Idol

Guardian Idol enters tapped.
{T}: Add {C}.
{2}: Guardian Idol becomes a 2/2 Golem artifact creature until end of turn.

Liliana's Specter

Flying
When Liliana's Specter enters, each opponent discards a card.

Mind Rot

Ebony Fly

Ebony Fly enters tapped.
{T}: Add {C}.
{4}: Roll a d6. Until end of turn, you may have Ebony Fly become an X/X Insect artifact creature with flying, where X is the result.
Whenever Ebony Fly attacks, another target attacking creature gains flying until end of turn.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Smallpox

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

Necrotic Hex

Each player sacrifices six creatures of their choice. You create six tapped 2/2 black Zombie creature tokens.

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.

Unnerve

Mind Rake

Target player discards two cards.
Overload {1}{B} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")