Duress

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

Lashwrithe

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each Swamp you control.
Equip {B/P}{B/P} ({B/P} can be paid with either {B} or 2 life.)

Murder

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Mountain

Tainted Well

Enchant land
When Tainted Well enters, draw a card.
Enchanted land is a Swamp.

Nightcreep

Until end of turn, all creatures become black and all lands become Swamps.

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}.

Swamp

Blood Moon

Contaminated Ground

Enchant land
Enchanted land is a Swamp.
Whenever enchanted land becomes tapped, its controller loses 2 life.

Cut Down

Destroy target creature with total power and toughness 5 or less.

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents of their choice.

Abhorrent Overlord

Flying
When Abhorrent Overlord enters, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
At the beginning of your upkeep, sacrifice a creature.