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.

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.

Indulging Patrician

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your end step, if you gained 3 or more life this turn, each opponent loses 3 life.

Sign in Blood

Target player draws two cards and loses 2 life.

Soul Warden

Whenever another creature enters the battlefield, you gain 1 life.

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Suture Priest

Whenever another creature enters the battlefield under your control, you may gain 1 life.
Whenever a creature enters the battlefield under an opponent's control, you may have that player lose 1 life.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Angelic Skirmisher

Flying
At the beginning of each combat, choose first strike, vigilance, or lifelink. Creatures you control gain that ability until end of turn.

Inspiring Overseer

Flying
When Inspiring Overseer enters the battlefield, you gain 1 life and draw a card.

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.

Sanguine Bond

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

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Swamp

Mortify

Plains

Griffin Aerie

At the beginning of your end step, if you gained 3 or more life this turn, create a 2/2 white Griffin creature token with flying.

Scoured Barrens

Scoured Barrens enters the battlefield tapped.
When Scoured Barrens enters the battlefield, you gain 1 life.
{T}: Add {W} or {B}.

Forsaken Sanctuary

Forsaken Sanctuary enters the battlefield tapped.
{T}: Add {W} or {B}.

Alseid of Life's Bounty

Lifelink
{1}, Sacrifice Alseid of Life's Bounty: Target creature or enchantment you control gains protection from the color of your choice until end of turn.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on Ajani's Pridemate.

Nyx-Fleece Ram

At the beginning of your upkeep, you gain 1 life.

Elspeth Resplendent

+1: Choose up to one target creature. Put a +1/+1 counter and a counter from among flying, first strike, lifelink, or vigilance on it.
−3: Look at the top seven cards of your library. You may put a permanent card with mana value 3 or less from among them onto the battlefield with a shield counter on it. Put the rest on the bottom of your library in a random order.
−7: Create five 3/3 white Angel creature tokens with flying.

Dawn of Hope

Whenever you gain life, you may pay {2}. If you do, draw a card.
{3}{W}: Create a 1/1 white Soldier creature token with lifelink.

Valkyrie Harbinger

Flying, lifelink
At the beginning of each end step, if you gained 4 or more life this turn, create a 4/4 white Angel creature token with flying and vigilance.

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

Seraph of the Scales

Flying
{W}: Seraph of the Scales gains vigilance until end of turn.
{B}: Seraph of the Scales gains deathtouch until end of turn.
Afterlife 2 (When this creature dies, create two 1/1 white and black Spirit creature tokens with flying.)

Orzhov Basilica

Orzhov Basilica enters the battlefield tapped.
When Orzhov Basilica enters the battlefield, return a land you control to its owner's hand.
{T}: Add {W}{B}.