I know exactly what you mean.
Most of the Korean dramas out there are based on young teens falling in love with each other, with usual love triangles, where one of the boys happen to be a millionaire, etc, etc.
I'm kind of sick of those dramas, too, because they usually have the same plot line.
But this one drama that I recently finished is called
Temptation of an Angel (천사의 유혹)
http://www.mysoju.com/temptation-of-an-angel/
It was once popular when it came out (about a year ago).
It's has a plot line that is definitely different from the other dramas, and has some thrillers in between. It's not a horror drama, though.
Basically about a woman who wants to gain revenge on the family that intentionally killed her parents when she was a kid.
So, she marries the son of that family and make him fall deeply in love with her.
Once he has fallen in love with her, she then takes revenge on both him and his family.
However, the man catches up to her plans and HE tries to get revenge back on her.
The whole plot line is incredible and it gave me the chills as I was watching..LOL
I can't explain it, but it's REALLY good. There's lots of action and was very intense from Episode 1 til the end. Worth watching!