I don't watch a huge amount of anime, but one I stumbled across that I really like is Sound of the Sky. It's about a group of teenage girls being slightly incompetent soldiers in a post-apocalyptic world. The characters are fantastic and it's aro-friendly with a strong emphasis on friendship/sisterhood rather than romance. It's also very picturesque and the emotional stuff is powerful - one episode actually moved me to tears.
I'm also a fan of Ouran High School Host Club. This one is a high school anime clearly aimed at straight girls (lots of very pretty boys and romantic fantasies) but the main female character has a strong ace/aro vibe, as well as being gender non-conforming. It's also funny, witty and plays with stereotypes in an entertaining way.