Swamp

Bone Splinters

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

Relentless Rats

This creature gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

Sign in Blood

Target player draws two cards and loses 2 life.

Village Rites

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

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.)

Defile

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

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Gray Merchant of Asphodel

When this creature 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.)

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Echoing Return

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.