Nightmare's Thirst

You gain 1 life. Target creature gets -X/-X until end of turn, where X is the amount of life you gained this turn.

Fountain of Renewal

At the beginning of your upkeep, you gain 1 life.
{3}, Sacrifice Fountain of Renewal: Draw a card.

As Diamond Mare enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Destroy target creature. You gain 3 life.

Flying
At the beginning of each end step, if you gained life this turn, create a 1/1 black Bat creature token with flying.

Flying
When Vampire Sovereign enters, target opponent loses 3 life and you gain 3 life.

Whenever you gain life, put a +1/+1 counter on this creature.

At the beginning of combat on your turn, if you control three or more creatures, this creature gets +1/+1 until end of turn and you gain 1 life.

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

Vigilance (Attacking doesn't cause this creature to tap.)
When Gallant Cavalry enters, create a 2/2 white Knight creature token with vigilance.

Target creature gets +2/+2 and gains flying until end of turn.

At the beginning of your upkeep, target opponent mills three cards, then you draw a card for each land card put into their graveyard this way.

Whenever you gain life, each opponent loses 1 life.

Flash (You may cast this spell any time you could cast an instant.)

Whenever a creature you control enters, you gain 1 life.

Flying
When Skymarch Bloodletter enters, target opponent loses 1 life and you gain 1 life.

Target creature gets +1/+7 until end of turn.

Destroy target artifact or enchantment. You gain 4 life.

Whenever Leonin Warleader attacks, create two 1/1 white Cat creature tokens with lifelink that are tapped and attacking.