Swamp

Black Knight

First strike (This creature deals combat damage before creatures without first strike.)
Protection from white (This creature can't be blocked, targeted, dealt damage, or enchanted by anything white.)

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Tortured Existence

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

Wasteland

{T}: Add {C}.
{T}, Sacrifice Wasteland: Destroy target nonbasic land.

Choking Sands

Destroy target non-Swamp land. If that land was nonbasic, Choking Sands deals 2 damage to the land's controller.

Necratog

Exile the top creature card of your graveyard: Necratog gets +2/+2 until end of turn.

Nekrataal

First strike
When Nekrataal enters, destroy target nonartifact, nonblack creature. That creature can't be regenerated.

Contagion

You may pay 1 life and exile a black card from your hand rather than pay this spell's mana cost.
Distribute two -2/-1 counters among one or two target creatures.

Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Vampire Bats

Flying (This creature can't be blocked except by creatures with flying or reach.)
{B}: Vampire Bats gets +1/+0 until end of turn. Activate no more than twice each turn.

Desecrated Tomb

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.