Frenemies to lovers

• Love in the Moonlight
• Accidentally in Love
• Sassy Go Go
• Suspicious Partner
• Mad Dog
• My Only Love Song
• Bring It On, Ghost

Weightlifting Kim Bok Joo kind of starts out that way, as they are never really enemies. 

In Mad For Each Other, they are initially enemies, then become frenenmies, and finally lovers.

Both dramas are great, if you haven't seen them.