Dramas where there is is some romance, romantic tension, or flirting but it's not the main focus of the drama (some of them are tagged as 'slight romance') and there would still be a plot if it was removed:
- My Mister (whether the feelings between the leads are romantic or platonic is open for interpretation)
- Mad Dog
- Ms. Perfect
- Page Turner
- City Hunter
- Hello Monster
- Misty
- When a Snail Falls in Love (despite the title, the romance is subtle)
I haven't watched them, but Life and Life on Mars are both tagged as 'slight romance'.