Elenda's Hierophant

Flying
Whenever you gain life, put a +1/+1 counter on Elenda's Hierophant.
When Elenda's Hierophant dies, create X 1/1 white Vampire creature tokens with lifelink, where X is its power.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Have

Blasphemous Edict

You may pay {B} rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield.
Each player sacrifices thirteen creatures of their choice.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

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.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Sanguine Syphoner

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

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

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.

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Sunscorch Regent and you gain 1 life.

Heliod, Sun-Crowned

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
Whenever you gain life, put a +1/+1 counter on target creature or enchantment you control.
{1}{W}: Another target creature gains lifelink until end of turn.