Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Death Denied

Return X target creature cards from your graveyard to your hand.

Kitchen Imp

Flying, haste
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Sign in Blood

Target player draws two cards and loses 2 life.

Swamp

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Blight Keeper

Flying
{7}{B}, {T}, Sacrifice Blight Keeper: Target opponent loses 4 life and you gain 4 life.

Duress

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

Carrion Imp

Flying
When Carrion Imp enters the battlefield, you may exile target creature card from a graveyard. If you do, you gain 2 life.

Foul Imp

Flying
When Foul Imp enters the battlefield, you lose 2 life.

Daggerdrome Imp

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Deepcavern Imp

Flying, haste
Echo—Discard a card. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Defile

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

Bonesplitter

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters the battlefield tapped unless you control three or more other Swamps.
When Witch's Cottage enters the battlefield untapped, you may put target creature card from your graveyard on top of your library.

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Putrid Imp

Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.

Ichor Slick

Target creature gets -3/-3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)
Madness {3}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)