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.

Have

Serra Avatar

Serra Avatar's power and toughness are each equal to your life total.
When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Don't Have

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Angelic Accord

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.

Boon Reflection

If you would gain life, you gain twice that much life instead.

Fountain of Renewal

At the beginning of your upkeep, you gain 1 life.
{3}, Sacrifice Fountain of Renewal: Draw a card.

Leonin Warleader

Whenever Leonin Warleader attacks, create two 1/1 white Cat creature tokens with lifelink that are tapped and attacking.

Ajani's Mantra

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

Sunbond

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Leonin Vanguard

At the beginning of combat on your turn, if you control three or more creatures, this creature gets +1/+1 until end of turn and you gain 1 life.

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Chalice of Death

Chalice of Life

{T}: You gain 1 life. Then if you have at least 10 life more than your starting life total, transform Chalice of Life.

Chalice of Life // Chalice of Death

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Resplendent Angel

Flying
At the beginning of each end step, if you gained 5 or more life this turn, create a 4/4 white Angel creature token with flying and vigilance.
{3}{W}{W}{W}: Until end of turn, Resplendent Angel gets +2/+2 and gains lifelink.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

Nyx-Fleece Ram

At the beginning of your upkeep, 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.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Snow-Covered Plains

Gideon's Company

Whenever you gain life, put two +1/+1 counters on Gideon's Company.
{3}{W}: Put a loyalty counter on target Gideon planeswalker.

Ajani's Pridemate

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

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Ajani's Sunstriker

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