Wrench Mind

Target player discards two cards unless they discard an artifact card.

Megrim

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

Unhinge

Target player discards a card.
Draw a card.

Wheel of Torture

At the beginning of each opponent's upkeep, Wheel of Torture deals X damage to that player, where X is 3 minus the number of cards in their hand.

Swamp

Rackling

At the beginning of each opponent's upkeep, Rackling deals X damage to that player, where X is 3 minus the number of cards in their hand.

Defile

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

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional 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.

Geth's Grimoire

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

Scepter of Fugue

{1}{B}, {T}: Target player discards a card. Activate only during your turn.

Pulse of the Dross

Target player reveals three cards from their hand and you choose one of them. That player discards that card. Then if that player has more cards in hand than you, return Pulse of the Dross to its owner's hand.

Skullcage

At the beginning of each opponent's upkeep, Skullcage deals 2 damage to that player unless they have exactly three or exactly four cards in hand.

Hypnotic Specter

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

Hymn to Tourach

Target player discards two cards at random.

Cunning Lethemancer

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

Mortivore

Mortivore's power and toughness are each equal to the number of creature cards in all graveyards.
{B}: Regenerate Mortivore. (The next time this creature would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Dark Ritual

The Rack

As The Rack enters, choose an opponent.
At the beginning of the chosen player's upkeep, The Rack deals X damage to that player, where X is 3 minus the number of cards in their hand.