Swamp

Bone Splinters

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

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Gempalm Polluter

Cycling {B}{B} ({B}{B}, Discard this card: Draw a card.)
When you cycle Gempalm Polluter, you may have target player lose life equal to the number of Zombies on the battlefield.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Mindleech Ghoul

Exploit (When this creature enters, you may sacrifice a creature.)
When Mindleech Ghoul exploits a creature, each opponent exiles a card from their hand.

Wight of Precinct Six

Wight of Precinct Six gets +1/+1 for each creature card in your opponents' graveyards.

Cry of Contrition

Target player discards a card.
Haunt (When this spell card is put into a graveyard after resolving, exile it haunting target creature.)
When the creature Cry of Contrition haunts dies, target player discards a card.

Crawl from the Cellar

Return target creature card from your graveyard to your hand. Put a +1/+1 counter on up to one target Zombie you control.
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Festering Mummy

When Festering Mummy dies, you may put a -1/-1 counter on target creature.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Duress

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