This is a gallery for Princess Luna's different physical appearances, forms, and outfits in the series, films, IDW comics, and other official material.
Swimsuit, Between Dark and Dawn
Leotard, Between Dark and Dawn
80s makeover, Between Dark and Dawn
Crescent moon on a dark purple background (usual)
Light blue crescent moon on a purple background (as Nightmare Moon)
Stylized sun (switched with Princess Celestia in S7E10