Definitely: Weightlifting Fairy Kim Bok Joo (Female Lead and Male Lead are childhood friends who reunite in college. ML had a childhood crush on this childhood friend, while the FM ends up falling for the ML's older brother. In the process ML (though teasing her at times) ends up supporting FM through thin and thick)
But others that might be like that (generally the girl has a crush on somebody else but ends up falling for the male lead) are ***********:
Surplus Princess
Plus Nine Boys
One More Happy Ending
Heart to Heart - Female MC suffers from a condition that makes her severely blush and as a result develops social phobia. She meets a psychiatrist who helps her overcome her phobia. (really cute drama imo)
Flower Boy Next Door - Female MC is a recluse that lives inside her house and rarely goes outside or talks to other people. One of the neighbors helps her overcome her shyness
Birth of a Beauty - After she found out that her husband has cheated on her, the Female MC seeks out a plastic surgeon to give her overweight former self a makeover as a part of a revenge scheme against her husband. The surgeon becomes a partner in crime and her helping hand in this revenge scheme.
MAJOR SPOILER ALERT for this drama (because the drama centers around the mystery of who the Female MC ends up with): Reply 1997 - in a (k-drama) world full of Male Leads always getting the girl, this drama is famous for the Second Male Lead finally getting the Female Lead
****** Please keep in mind that it's been a while since I have seen some of these dramas so I don't remember all the details and whether what you requested rings true for all of these dramas.