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.

Plains

Soul Warden

Whenever another creature enters, you gain 1 life.

Ajani's Welcome

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

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, this creature gets +2/+2 and gains lifelink.

Banishing Light

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

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.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, this creature gets +5/+5 and has flying.

Prison Realm

When this enchantment enters, exile target creature or planeswalker an opponent controls until this enchantment leaves the battlefield.
When this enchantment enters, scry 1.

Ajani's Pridemate

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

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.

Cavalier of Dawn

Vigilance
When this creature enters, destroy up to one target nonland permanent. Its controller creates a 3/3 colorless Golem artifact creature token.
When this creature dies, return target artifact or enchantment card from your graveyard to your hand.

Healer's Hawk

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

Leyline of Sanctity

If this card is in your opening hand, you may begin the game with it on the battlefield.
You have hexproof. (You can't be the target of spells or abilities your opponents control.)

Castle Ardenvale

This land enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.