Some K-Dramas that I've watched and liked, without romance (or only a little bit) :
Signal (detective, fantasy)
School 2013 (school, life, yourh)
Two Weeks (action, thriller)
Page Turner (school, music, drama)
Nightmare Teacher (school, mystery, supernatural)
Vampire Prosecutor 1 & 2 (investigation, mystery, vampire)
The Suspicious Housekeeper (family, melodrama, myster)
The Master Of Revenge (food, melodrama, mystery)
Angry Mom (comedy, family, school)
Bad Guys (action, crime, psychological)
Incomplete Life / Misaeng (business, drama, life)
The Village : Achiara's Secret (crime, horror, mystery)