Not sure if it is your style but here it goes:
- Arranged Marriage where they slowly fall in love
- Lumine is a princess who saves Xiao, half bird boy, from his previous master, she starts to take care of him and they slowly fall in love, but it is forbidden because she is royalty
- ice skating au where they are paired together and slowly get closer
- Lumine and Aether were separated when they were young, she looks for him and meets xiao who knows Aether and is also looking for him - i like slow burn lol