6. Bossam: Steal the Fate - FL's FIL I liked that he was calm and smart, not like those hysterical screaming villains
7. Under the Queen's Umbrella - Queen Dowager. Acted so well and chemistry with FL was on fire, so intense scenes!
Bonus, since he was more like an antagonist than villain:
Bloody Heart - Park Kye Won, can't call him a villain, he was more like an antagonist. First, his acting and charisma,wow. Second, the character had strong and reasonable motivation for his actions, not just evil being evil. Plus, his non romantic chemistry with FL, he overshadowed ML for me haha