Obzedat, Ghost Council

When Obzedat, Ghost Council enters, target opponent loses 2 life and you gain 2 life.
At the beginning of your end step, you may exile Obzedat. If you do, return it to the battlefield under its owner's control at the beginning of your next upkeep. It gains haste.

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Spirit Link

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Whenever enchanted creature deals damage, you gain that much life.

Angel's Mercy

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Famished Paladin

Famished Paladin doesn't untap during your untap step.
Whenever you gain life, untap Famished Paladin.

Perimeter Captain

Defender
Whenever a creature you control with defender blocks, you may gain 2 life.

Corpse Knight

Whenever another creature you control enters, each opponent loses 1 life.

Blood Burglar

During your turn, Blood Burglar has lifelink.(Damage dealt by this creature also causes you to gain that much life.)

Ajani's Welcome

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

Ajani, Wise Counselor

+2: You gain 1 life for each creature you control.
−3: Creatures you control get +2/+2 until end of turn.
−9: Put X +1/+1 counters on target creature, where X is your life total.

Resplendent Mentor

White creatures you control have "{T}: You gain 1 life."

Speaker of the Heavens

Vigilance, lifelink (Attacking doesn't cause this creature to tap. Damage dealt by this creature also causes you to gain that much life.)
{T}: Create a 4/4 white Angel creature token with flying. Activate only if you have at least 7 life more than your starting life total and only as a sorcery.

Cursebreak

Destroy target enchantment. You gain 2 life.

Healer's Hawk

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