Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Gifted Aetherborn

Sol Ring

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Nighthawk Scavenger

Flying, deathtouch, lifelink
Nighthawk Scavenger's power is equal to 1 plus the number of card types among cards in your opponents' graveyards.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Ajani's Pridemate

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

Vampire Nighthawk

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)