Angelic layer and crest of the stars/banner of the stars
The first is a 25 episode series that took a medicocure manga and made it into an amazing anime by changing a few small details* so things actually made more sense.
For a battle anime it's not especially action packed but it's got some amazing character development. It's amazing how expressive the Angels are for dolls that can't speak.
Crest of the stars/Banner of the stars is a series of ovas. It's sort of a space opera about the story of two literally star crossed lovers Jinto and Lafiel and their growing relationship with each other.