Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Plains

Sign in Blood

Target player draws two cards and loses 2 life.

Nip Gwyllion

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

Swamp

Imperious Oligarch

Vigilance
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Unmake

Tendrils of Corruption

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

Nightsky Mimic

Whenever you cast a spell that's both white and black, Nightsky Mimic has base power and toughness 4/4 until end of turn and gains flying until end of turn.

Soul Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.
Whenever enchanted creature is dealt damage, you gain that much life.

Castigate

Target opponent reveals their hand. You choose a nonland card from it and exile that card.

Edge of the Divinity

Enchant creature
As long as enchanted creature is white, it gets +1/+2.
As long as enchanted creature is black, it gets +2/+1.

Pillory of the Sleepless

Enchant creature
Enchanted creature can't attack or block.
Enchanted creature has "At the beginning of your upkeep, you lose 1 life."

Duress

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

Mourning Thrull

({W/B} can be paid with either {W} or {B}.)
Flying
Whenever Mourning Thrull deals damage, you gain that much life.

Call to the Feast

Create three 1/1 white Vampire creature tokens with lifelink.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")