Princess Luna

Flying
When this creature transforms into Princess Luna, choose up to six cards you own from outside the game with a moon in their art, then exile those cards. As long as those cards remain exiled, you may cast them, and your friends may cast them with your permission. (Gifts are appreciated.)

Nightmare Moon

Flying
As long as it's nighttime, Nightmare Moon gets +2/+2 and has menace.
{6}: Transform Nightmare Moon. Anypony may activate this ability or help pay the cost. When they do, they become your friend.

Nightmare Moon // Princess Luna

Fan Favorite

Assist (Another player can pay up to {3} of this spell's cost.)
{2}: This creature gets +1/+1 until end of turn. Any player may activate this ability.