Fukigen Cinderella, Boku Girl Recommendations
Both manga's main aspect are genderbender:
In Boku Girl the male protagonist changes into a girl by evil doing of a higher being (god/demon idk what it's called anymore) and has to overcome some hurdles in order to try his gender change.
In Fukigen Cinderella the boy is turned into a girl but only from 12 AM to 12 PM (12-24).
Well there's nothing more to say (apart from that both are in my top 5 gender bender).