Impassioned Orator

Whenever another creature you control enters, you 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.

Plains

Lifecreed Duo

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

Bishop of Wings

Whenever an Angel you control enters, you gain 4 life.
Whenever an Angel you control dies, create a 1/1 white Spirit creature token with flying.

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.

Ajani's Pridemate

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

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.

Kor Celebrant

Whenever Kor Celebrant or another creature you control enters, you gain 1 life.

Ajani's Welcome

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

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.

Distinguished Conjurer

Whenever another creature you control enters, you gain 1 life.
{4}{W}, {T}: Exile another target creature you control, then return it to the battlefield under its owner's control.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Answered Prayers

Whenever a creature you control enters, you gain 1 life. If Answered Prayers isn't a creature, it becomes a 3/3 Angel creature with flying in addition to its other types until end of turn.