Sanguine Syphoner

Whenever this creature attacks, each opponent loses 1 life and you gain 1 life.

Exquisite Blood

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

Dazzling Angel

Flying
Whenever another creature you control enters, you gain 1 life.

Mortify

Ajani's Pridemate

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

Healer's Hawk

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

Moment of Triumph

Target creature gets +2/+2 until end of turn. You gain 2 life.

Vengeful Bloodwitch

Whenever this creature or another creature you control dies, target opponent loses 1 life and you gain 1 life.

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.)

Scoured Barrens

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {B}.

Hinterland Sanctifier

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

Cat Collector

When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever you gain life for the first time during each of your turns, create a 1/1 white Cat creature token.

Swamp

Moment of Craving

Target creature gets -2/-2 until end of turn. You gain 2 life.

Tribute to Hunger

Target opponent sacrifices a creature of their choice. You gain life equal to that creature's toughness.

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}.

Sun-Blessed Healer

Kicker {1}{W} (You may pay an additional {1}{W} as you cast this spell.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When this creature enters, if it was kicked, return target nonland permanent card with mana value 2 or less from your graveyard to the battlefield.

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Plains

Fiendish Panda

Whenever you gain life, put a +1/+1 counter on this creature.
When this creature dies, return another target non-Bear creature card with mana value less than or equal to this creature's power from your graveyard to the battlefield.

Twinblade Paladin

Whenever you gain life, put a +1/+1 counter on this creature.
As long as you have 25 or more life, this creature has double strike. (It deals both first-strike and regular combat damage.)