Dimir Guildmage

({U/B} can be paid with either {U} or {B}.)
{3}{U}: Target player draws a card. Activate only as a sorcery.
{3}{B}: Target player discards a card. Activate only as a sorcery.

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.

Dark Deal

Each player discards all the cards in their hand, then draws that many cards minus one.

Ghost-Lit Stalker

{4}{B}, {T}: Target player discards two cards. Activate only as a sorcery.
Channel — {5}{B}{B}, Discard this card: Target player discards four cards. Activate only as a sorcery.

Davriel, Rogue Shadowmage

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, Davriel deals 2 damage to them.
−1: Target player discards a card.

Marvin, Murderous Mimic

Marvin has all activated abilities of creatures you control that don't have the same name as this creature.

Mind Knives

Target opponent discards a card at random.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Thought Erasure

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Whispers of Emrakul

Target opponent discards a card at random.
Delirium — If there are four or more card types among cards in your graveyard, that player discards two cards at random instead.

Sol Ring

Quest for the Nihil Stone

Whenever an opponent discards a card, you may put a quest counter on this enchantment.
At the beginning of each opponent's upkeep, if that player has no cards in hand and this enchantment has two or more quest counters on it, you may have that player lose 5 life.

Mind Shatter

Target player discards X cards at random.

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Tinybones, Bauble Burglar

Whenever an opponent discards a card, exile it from their graveyard with a stash counter on it.
During your turn, you may play cards you don't own with stash counters on them from exile, and mana of any type can be spent to cast those spells.
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Sakashima the Impostor

You may have Sakashima the Impostor enter as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return Sakashima the Impostor to its owner's hand at the beginning of the next end step."

Liliana's Caress

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

Cabal Therapist

Menace
At the beginning of your first main phase, you may sacrifice a creature. When you do, choose a nonland card name, then target player reveals their hand and discards all cards with that name.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Tolarian Winds

Discard all the cards in your hand, then draw that many cards.

Tinybones, the Pickpocket

Deathtouch
Whenever Tinybones deals combat damage to a player, you may cast target nonland permanent card from that player's graveyard, and mana of any type can be spent to cast that spell.

Mind Twist

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

Abyssal Nocturnus

Whenever an opponent discards a card, this creature gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Divest

Target player reveals their hand. You choose an artifact or creature card from it. That player discards that card.

Harsh Scrutiny

Target opponent reveals their hand. You choose a creature card from it. That player discards that card. Scry 1.

Likeness Looter

Flying
{T}: Draw a card, then discard a card.
{X}: This creature becomes a copy of target creature card in your graveyard with mana value X, except it has flying and this ability. Activate only as a sorcery.

Lore Broker

{T}: Each player draws a card, then discards a card.

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav become a copy of that card, except its name is Lazav, Dimir Mastermind, it's legendary in addition to its other types, and it has hexproof and this ability.

Blackmail

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

Dimir Cutpurse

Whenever this creature deals combat damage to a player, that player discards a card and you draw a card.

Hymn to Tourach

Target player discards two cards at random.

Cabal Therapy

Choose a nonland card name. Target player reveals their hand and discards all cards with that name.
Flashback—Sacrifice a creature. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Nebuchadnezzar

{X}, {T}: Choose a card name. Target opponent reveals X cards at random from their hand. Then that player discards all cards with that name revealed this way. Activate only during your turn.

Dream Salvage

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

Wishclaw Talisman

This artifact enters with three wish counters on it.
{1}, {T}, Remove a wish counter from this artifact: Search your library for a card, put it into your hand, then shuffle. An opponent gains control of this artifact. Activate only during your turn.

Duress

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

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 this creature.