Duress

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

Dark Deal

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

When Drainpipe Vermin dies, you may pay {B}. If you do, target player discards a card.

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

When Ravenous Rats enters the battlefield, target opponent discards a card.

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

Whenever Howling Golem attacks or blocks, each player draws a card.

Destroy target creature. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

At the beginning of each player's draw step, that player draws two additional cards.

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

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

Target creature gets -X/-X until end of turn, where X is 7 minus the number of cards in that creature's controller's hand.

Target player draws X cards and loses X life.