Plaguecrafter

When Plaguecrafter enters the battlefield, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Dreadwurm

Landfall — Whenever a land enters the battlefield under your control, Dreadwurm gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Swamp

Cruel Grimnarch

Deathtouch
When Cruel Grimnarch enters the battlefield, each opponent discards a card. For each opponent who can't, you gain 4 life.

Burglar Rat

When Burglar Rat enters the battlefield, each opponent discards a card.

Village Rites

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

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

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.

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.

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

Abyssal Nocturnus

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

Honden of Night's Reach

At the beginning of your upkeep, target opponent discards a card for each Shrine you control.

Drainpipe Vermin

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