Duress

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

Undertaker

{B}, {T}, Discard a card: Return target creature card from your graveyard to your hand.

Swamp

Augur of Skulls

{1}{B}: Regenerate Augur of Skulls.
Sacrifice Augur of Skulls: Target player discards two cards. Activate only during your upkeep.

Disentomb

Return target creature card from your graveyard to your hand.

Gnat Miser

Each opponent's maximum hand size is reduced by one.

Burglar Rat

When this creature enters, each opponent discards a card.

Diregraf Scavenger

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Diregraf Scavenger enters, exile up to one target card from a graveyard. If a creature card was exiled this way, each opponent loses 2 life and you gain 2 life.

Dark Withering

Destroy target nonblack creature.
Madness {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.)

Gilt-Blade Prowler

{1}, {T}, Pay 1 life: Draw a card. Activate only if you've discarded a card this turn.

Call to the Netherworld

Return target black creature card from your graveyard to your hand.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Delirium Skeins

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.