any drama where 1. SML ends up with the FL
2. both MLs have equal screen time and the unlikely one ( could be considered SML) ends up with the FL
If you can stand Korean melodramas then Passionate Love (2013) probably fits the bill
Star April
1-love alarm
2-king in love
Also, for me personally, it was school 2015. Maybe it was obvious to others, but I was not expecting that ending.
Dramas where it wasn't obvious from the beginning who the FL would end up with:
Chuno/The Slave Hunters