Resplendent Mentor

White creatures you control have "{T}: You gain 1 life."

Ajani's Welcome

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

Lightning Helix

Lightning Helix deals 3 damage to any target and you gain 3 life.

Student of Warfare

Level up {W} ({W}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 2-6
3/3
First strike
LEVEL 7+
4/4
Double strike

Speaker of the Heavens

Vigilance, lifelink (Attacking doesn't cause this creature to tap. Damage dealt by this creature also causes you to gain that much life.)
{T}: Create a 4/4 white Angel creature token with flying. Activate only if you have at least 7 life more than your starting life total and only as a sorcery.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Elemental Mastery

Enchant creature
Enchanted creature has "{T}: Create X 1/1 red Elemental creature tokens with haste, where X is this creature's power. Exile them at the beginning of the next end step."

Soul Warden

Whenever another creature enters, you gain 1 life.

Attended Healer

Whenever you gain life for the first time each turn, create a 1/1 white Cat creature token.
{2}{W}: Another target Cleric gains lifelink until end of turn.

Impassioned Orator

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

Midnight Guard

Whenever another creature enters, untap Midnight Guard.

Famished Paladin

Famished Paladin doesn't untap during your untap step.
Whenever you gain life, untap Famished Paladin.

Clifftop Retreat

Clifftop Retreat enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Daxos, Blessed by the Sun

Daxos's toughness is equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Whenever another creature you control enters or dies, you gain 1 life.

Anointer Priest

Whenever a creature token you control enters, you gain 1 life.
Embalm {3}{W} ({3}{W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Human Cleric with no mana cost. Embalm only as a sorcery.)

Path of Bravery

As long as your life total is greater than or equal to your starting life total, creatures you control get +1/+1.
Whenever one or more creatures you control attack, you gain life equal to the number of attacking creatures.

Plains

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.