Honorable mention to White Light by Superfly from Tales of Zestiria though it's a video game opening and not an anime.

Oh and I forgot about Masayume Chasing by BoA from Fairy Tail!

For me it would be one of these 5:

- Moonlight Densetsu by DALI | Sailor Moon
- Butterfly by Wada Koji | Digimon Adventure
- Kyouran Hey Kids by Oral Cigarettes | Noragami Aragoto
- Bye Bye Yesterday by 3 Nen E Gumi Uta Tan | Assassination Classroom
- go forward by Kimeru | Yu-Gi-Oh Vrains

Wait, making Perfectly Ultimate Great Moth a fusion card for Rush is actually really smart

I support women's rights and wrongs