Ajani's Pridemate

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

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.)

Sungrace Pegasus

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

Plains

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Light of Promise

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

Ajani's Sunstriker

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

Healer's Hawk

Heron of Hope

Flying
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: This creature gains lifelink until end of turn.

Voice of the Blessed

Whenever you gain life, put a +1/+1 counter on this creature.
As long as this creature has four or more +1/+1 counters on it, it has flying and vigilance.
As long as this creature has ten or more +1/+1 counters on it, it has indestructible.

Adamant Will

Target creature gets +2/+2 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Silverstrike

Destroy target attacking creature. You gain 3 life.

Charmed Stray

Lifelink
When this creature enters, put a +1/+1 counter on each other creature you control named Charmed Stray.

Aerial Assault

Destroy target tapped creature. You gain 1 life for each creature you control with flying.

Glorious Enforcer

Flying, lifelink
At the beginning of each combat, if you have more life than an opponent, this creature gains double strike until end of turn.