Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Darkness

Prevent all combat damage that would be dealt this turn.

Thriving Moor

Thriving Moor enters the battlefield tapped.
As Thriving Moor enters the battlefield, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Dread Presence

Whenever a Swamp enters the battlefield under your control, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Chainer, Dementia Master

All Nightmares get +1/+1.
{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.
When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Crushing Disappointment

Each player loses 2 life. You draw two cards.

Plague Mare

Plague Mare can't be blocked by white creatures.
When Plague Mare enters the battlefield, creatures your opponents control get -1/-1 until end of turn.

Falthis, Shadowcat Familiar

Commanders you control have menace and deathtouch.
Partner (You can have two commanders if both have partner.)

Grimdancer

Grimdancer enters the battlefield with your choice of two different counters on it from among menace, deathtouch, and lifelink.

Swamp

Hunted Nightmare

Menace
When Hunted Nightmare enters the battlefield, target opponent puts a deathtouch counter on a creature they control.

Infernal Darkness

Cumulative upkeep—Pay {B} and 1 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
If a land is tapped for mana, it produces {B} instead of any other type.

Gravegouger

When Gravegouger enters the battlefield, exile up to two target cards from a single graveyard.
When Gravegouger leaves the battlefield, return the exiled cards to their owner's graveyard.

Herald's Horn

As Herald's Horn enters the battlefield, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Nightmare Shepherd

Flying
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that creature, except it's 1/1 and it's a Nightmare in addition to its other types.

Cover of Darkness

As Cover of Darkness enters the battlefield, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Banehound

Vanquisher's Banner

As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.