Angel of Vitality

Flying
If you would gain life, you gain that much life plus 1 instead.
This creature gets +2/+2 as long as you have 25 or more life.

Serra's Guardian

Flying (This creature can't be blocked except by creatures with flying or reach.)
Vigilance (Attacking doesn't cause this creature to tap.)
Other creatures you control have vigilance.

Savannah Sage

When this creature enters, you gain 2 life.

Ajani, Inspiring Leader

+2: You gain 2 life. Put two +1/+1 counters on up to one target creature.
−3: Exile target creature. Its controller gains 2 life.
−10: Creatures you control gain flying and double strike until end of turn.

Impassioned Orator

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

Moment of Heroism

Target creature gets +2/+2 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Goldmane Griffin

Flying, vigilance
When this creature enters, you may search your library and/or graveyard for a card named Ajani, Inspiring Leader, reveal it, and put it into your hand. If you search your library this way, shuffle.

Twinblade Paladin

Whenever you gain life, put a +1/+1 counter on this creature.
As long as you have 25 or more life, this creature has double strike. (It deals both first-strike and regular combat damage.)

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Plains

Daybreak Chaplain

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

Dawning Angel

Flying
When this creature enters, you gain 4 life.

Loxodon Lifechanter

When this creature enters, you may have your life total become the total toughness of creatures you control.
{5}{W}: This creature gets +X/+X until end of turn, where X is your life total.