The best korean drama villains

For Me:

Kwon Jae-hee (played by Nam Gung Min) from The Girl Who Sees Smells

Nam Gyu-man (played by Nam Gung Min) from Remember: War of the Son

I agree re: My Love from the Star villain. He is so hilariously evil, he just needs a mustache he can twirl. 

The mums from Pinocchio - it's such a cliche in kdramaland, but parents do make good villains I have to admit 

Jang Hyun Sung - signal (i hated him the whole time)
Song Yoon Ah - the k2 (fav female villian, a extreme manipulative character)
Jang Mi Kwan - Strong Woman Do Bong Soon (loved his portrayal.......just wished it was done in a crime triller than rom-com kinda series)

from the my current completed list

Song Yoon ah from K2 was perharps the best villian i have ever watched in a kdrama. She was not evil, and her motives made sense. I could sympathise with her and in the scene when she tells yoona that she has the capacity to become like her, I was just like wow, she made perfect sense because yoona was ridiculously similar to her in circumstance. Her acting also sold me. Song Yoon Ah is one of my fav actress

Cha Minho from Defendant and Ji Se Gwang from Incarnation of Money.

Lee Jae Kyung - My love from the star
Kwon Jae-hee -The Girl Who Sees Smells

Shin sung rok of You Who Came from the Star and Liar Game

Mishil - Queen Seon Deok!!! I loved her so much. Probably my favorite villain ever. 
Ki Cheol - Faith. This is a villain that I really appreciated the first time I watched but not as much the second time. idk I liked that he was vulnerable and we really got to see him struggle (not because of the main characters, but because of his own worries. It made him more like a character than just a villain whose only purpose is to make a plot.). I just appreciated that he had a purpose behind his motives I guess.