Mesa Unicorn

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

Archangel

Destroy target tapped creature. You gain 2 life.

Creatures you control get +2/+2 until end of turn.

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Flying
Vigilance (Attacking doesn't cause this creature to tap.)

Vigilance (Attacking doesn't cause this creature to tap.)

Vigilance
Other creatures you control get +0/+2 and have vigilance.