Haazda Officer

When Haazda Officer enters, target creature you control gets +1/+1 until end of turn.

Plains

Target creature gets +2/+2 and gains flying until end of turn.

Vigilance (Attacking doesn't cause this creature to tap.)
When Gallant Cavalry enters, create a 2/2 white Knight creature token with vigilance.

Flying
When Angel of Mercy enters, you gain 3 life.

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