Healer's Hawk

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

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Exemplar of Light

Flying
Whenever you gain life, put a +1/+1 counter on this creature.
Whenever you put one or more +1/+1 counters on this creature, draw a card. This ability triggers only once each turn.

Sanguine Syphoner

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

Swamp

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Elenda, Saint of Dusk

Lifelink, hexproof from instants
As long as your life total is greater than your starting life total, Elenda gets +1/+1 and has menace. Elenda gets an additional +5/+5 as long as your life total is at least 10 greater than your starting life total.

Vengeful Bloodwitch

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

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.

Helpful Hunter

Plains

Bake into a Pie

Destroy target creature. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

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.

Scoured Barrens

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

Banishing Light

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

Ajani's Pridemate

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

Felidar Savior

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When this creature enters, put a +1/+1 counter on each of up to two other target creatures you control.