Plains

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

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.

Isolated Chapel

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

Angel of Vitality

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

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Swamp

Tainted Field

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

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.

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.

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.

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.

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.

Command Tower

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

Temple of Silence

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {B}.

Exquisite Blood

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

Arcane Signet

Kambal, Consul of Allocation

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

Bloodthirsty Aerialist

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

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.")

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.