Dark Ritual

Consuming Corruption

Consuming Corruption deals X damage to target creature or planeswalker and you gain X life, where X is the number of Swamps you control.

Seizan, Perverter of Truth

At the beginning of each player's upkeep, that player loses 2 life and draws two cards.

Scrawling Crawler

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.

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}.

Defile

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

Jet Medallion

Black spells you cast cost {1} less to cast.

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.