When A Snail Falls In Love (Chinese) - A detective team that works on a complex case that spans over the entire show. Romance is minimal but strong. ML was the FL's instructor. Warning: It's not open-ended, but the ending does leave some unanswered questions. It might be hints for a season 2, but I'm a bit skeptical for now.
Love Me If You Dare (Chinese) - Similar to "When A Snail Falls In Love", but this one is more psychological. A little bit more romance than WAFSIL too, but still Romance is the secondary genre. FL works under the ML and assists him with cases. It's one mystery per episode, but all the mysteries lead up to the final one.
Blood (Korean) - Medical drama. FL is a really talented doctor who's attained a really high position in the hospital at a young age. ML is a vampire who's abilities surpass hers (medically) quite a bit. More romance and less medical, but there's still plenty of it. Warning: This one ends very open-ended. It's not clear whether the *SPOILER* ML died or not *SPOILER END*
You're All Surrounded (Korean) - A detective team solves mysteries. Most of the members, including the FL and ML are newbies. Despite that, the ML is quite gifted in. ML and FL know each other from childhood, but something happened to ML in the past so he changed his identity. Romance is a little less prominent than the detective aspect, but it's there like 35%-40% of the time.
The K2 (Korean)- Not cops, but a security company that deals with the wealthy. (bodyguards, Investigating, etc.) Romance was mediocre in my opinion; ML was the FL's bodyguard and tbh she was useless af. The psychological and mystery aspect, on the other hand, was top notch.
Edit: I'm kind of hesitating on recommending Blood, because while it was slightly enjoyable, it was far from great.