Limiting myself to just one here I guess. View attachment 763783
Also contemplated Android 18 but calling her a villain doesn't actually make a lot of sense, and Viconia DeVir is definitely evil but she isn't an antagonist (until Keldorn gets sick of her lol).
One of my favorite bad guys, from my teenage years, was Richard Lynch. Back in the 60's he took some LSD and tripped out and set his face on fire. So his skin was pretty rough and he was thrown into bad guy roles. But he was so talented. I always thought he was sexy. Sadly he died, alone, in 2012 and and found a few days later. I think it was heart failure.
My second favorite bad guy was Alan Rickman in his Die Hard role as the evil German, Hans Gruber.