Powerstone Shard

{T}: Add {C} for each artifact you control named Powerstone Shard.

Sinuous Vermin

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Sinuous Vermin is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Bad Moon

Memorial to Folly

Memorial to Folly enters tapped.
{T}: Add {B}.
{2}{B}, {T}, Sacrifice Memorial to Folly: Return target creature card from your graveyard to your hand.

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Soul Salvage

Return up to two target creature cards from your graveyard to your hand.

Typhoid Rats

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

Necropolis Regent

Flying
Whenever a creature you control deals combat damage to a player, put that many +1/+1 counters on it.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Raise Dead

Return target creature card from your graveyard to your hand.

Swamp

Short Sword

Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Cast Down

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Vraska's Contempt

Exile target creature or planeswalker. You gain 2 life.

Pestilence Rats

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

Sparring Construct

When Sparring Construct dies, put a +1/+1 counter on target creature you control.

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Vampire Nighthawk

Dark Ritual

Dread Shade

{B}: Dread Shade gets +1/+1 until end of turn.

Razortooth Rats

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.