Exquisite Blood

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

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Isolated Chapel

Isolated Chapel enters the battlefield tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Sol Ring

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Rodolf Duskbringer

Flying, deathtouch, lifelink
Whenever you gain life, Rodolf Duskbringer gains indestructible until end of turn.
At the beginning of your end step, you may pay {1}{W/B}. When you do, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn.

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Tainted Field

{T}: Add {C}.
{T}: Add {W} or {B}. Activate only if you control a Swamp.

Angel of Vitality

Flying
If you would gain life, you gain that much life plus 1 instead.
Angel of Vitality gets +2/+2 as long as you have 25 or more life.

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Kambal, Consul of Allocation

Whenever an opponent casts a noncreature spell, that player loses 2 life and you gain 2 life.

Celestine, the Living Saint

Flying, lifelink
Healing Tears — At the beginning of your end step, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn.

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.

Command Tower

Sanguine Bond

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

Plains

Swamp

Bloodthirsty Aerialist

Flying
Whenever you gain life, put a +1/+1 counter on Bloodthirsty Aerialist.

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Temple of Silence

Temple of Silence enters the battlefield tapped.
When Temple of Silence enters the battlefield, scry 1.
{T}: Add {W} or {B}.

Liesa, Shroud of Dusk

Rather than pay {2} for each previous time you've cast this spell from the command zone this game, pay 2 life that many times.
Flying, lifelink
Whenever a player casts a spell, they lose 2 life.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")