Knight of Dawn's Light

First strike
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: Knight of Dawn's Light gets +1/+1 until end of turn.

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.

Spiritual Guardian

When Spiritual Guardian enters, you gain 4 life.

Hallowed Priest

Whenever you gain life, put a +1/+1 counter on Hallowed Priest.

Metropolis Reformer

Flying, vigilance
You have hexproof.
Whenever Metropolis Reformer is dealt damage, you gain that much life.

Impassioned Orator

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

Soulmender

Kaya, Intangible Slayer

Hexproof
+2: Each opponent loses 3 life and you gain 3 life.
0: You draw two cards. Then each opponent may scry 1.
−3: Exile target creature or enchantment. If it wasn't an Aura, create a token that's a copy of it, except it's a 1/1 white Spirit creature with flying in addition to its other types.

Mesa Cavalier

Flying
When Mesa Cavalier enters, you gain 2 life.

Serra Faithkeeper

Invasion of Dominaria

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Dominaria enters, you gain 4 life and draw a card.

Invasion of Dominaria // Serra Faithkeeper

Vraan, Executioner Thane

Whenever one or more other creatures you control die, each opponent loses 2 life and you gain 2 life. This ability triggers only once each turn.

Tale of Tinúviel

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Target creature you control gains indestructible for as long as you control Tale of Tinúviel.
II — Return target creature card from your graveyard to the battlefield.
III — Up to two target creatures you control each gain lifelink until end of turn.

Vampire Opportunist

{6}{B}: Each opponent loses 2 life and you gain 2 life.

Etched Host Doombringer

When Etched Host Doombringer enters, choose one —
• Target opponent loses 2 life and you gain 2 life.
• Choose target battle. If an opponent protects it, remove three defense counters from it. Otherwise, put three defense counters on it.