Bottomless Pit

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

Cackling Fiend

When Cackling Fiend enters, each opponent discards a card.

Megrim

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

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Chilling Apparition

{B}: Regenerate Chilling Apparition.
Whenever Chilling Apparition deals combat damage to a player, that player discards a card.

Ill-Gotten Gains

Exile Ill-Gotten Gains. Each player discards their hand, then returns up to three cards from their graveyard to their hand.

Insidious Bookworms

When Insidious Bookworms dies, you may pay {1}{B}. If you do, target player discards a card at random.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Noxious Toad

When Noxious Toad dies, each opponent discards a card.

Sol Ring

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Don't Have

Chains of Mephistopheles

If a player would draw a card except the first one they draw in each of their draw steps, that player discards a card instead. If the player discards a card this way, they draw a card. If the player doesn't discard a card this way, they mill a card.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Earsplitting Rats

When Earsplitting Rats enters, each player discards a card.
Discard a card: Regenerate Earsplitting Rats.

Chain of Smog

Target player discards two cards. That player may copy this spell and may choose a new target for that copy.

Mind Stone

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

Herald of Anguish

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Screeching Buzzard

Flying
When Screeching Buzzard dies, each opponent discards a card.

Scandalmonger

{2}: Target player discards a card. Any player may activate this ability but only as a sorcery.

Noxious Vapors

Each player reveals their hand, chooses one card of each color from it, then discards all other nonland cards.

Commander's Sphere

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

Words of Waste

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

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.)

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Feed the Swarm

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

Strongarm Tactics

Each player discards a card. Then each player who didn't discard a creature card this way loses 4 life.

Ancient Craving

You draw three cards and you lose 3 life.

Haunted Cadaver

Whenever Haunted Cadaver deals combat damage to a player, you may sacrifice it. If you do, that player discards three cards.
Morph {1}{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.)

Odylic Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Whenever Odylic Wraith deals 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.

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.)

Toxic Stench

Target nonblack creature gets -1/-1 until end of turn.
Threshold — If seven or more cards are in your graveyard, instead destroy that creature. It can't be regenerated.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ambition's Cost

Headhunter

Whenever Headhunter deals combat damage to a player, that player discards a card.
Morph {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.)

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Swamp

Ghastly Demise

Destroy target nonblack creature if its toughness is less than or equal to the number of cards in your graveyard.

Cunning Advisor

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

Abyssal Specter

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

Mindstab Thrull

Whenever Mindstab Thrull attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards.

Expunge

Destroy target nonartifact, nonblack creature. It can't be regenerated.
Cycling {2} ({2}, Discard this card: Draw a card.)

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Wei Night Raiders

Horsemanship (This creature can't be blocked except by creatures with horsemanship.)
Whenever Wei Night Raiders deals damage to an opponent, that player discards a card.

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.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

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.

Cao Cao, Lord of Wei

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

Unnerve

Blackmail

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

Mindslicer

When Mindslicer dies, each player discards their hand.

Entropic Specter

Flying
As Entropic Specter enters, choose an opponent.
Entropic Specter's power and toughness are each equal to the number of cards in the chosen player's hand.
Whenever Entropic Specter deals damage to a player, that player 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.

Alley Grifters

Whenever Alley Grifters becomes blocked, defending player discards a card.

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Hypnotic Specter

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

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.

Gravestorm

At the beginning of your upkeep, target opponent may exile a card from their graveyard. If that player doesn't, you may draw a card.