30. Nurse Ratched (“One Flew Over the Cuckoo’s Nest”)
29. T-1000 (“Terminator 2: Judgment Day”)
28. Calvin Candie (“Django Unchained”)
27. Gollum (“The Lord of the Rings” franchise)
26. Immortan Joe (“Mad Max: Fury Road”)
25. Michael Myers (“Halloween” franchise)
24. Lord Voldemort (“Harry Potter” franchise)
23. Predator (“Predator” franchise)
22. Annie Wilkes (“Misery”)
21. John Doe (“Seven”)
20. Jason Voorhees (“Friday the 13th” franchise)
19. Thanos (“The Avengers” franchise)
18. The Alien (“Alien” franchise)
17. Phyllis Dietrichson (“Double Indemnity”)
16. Keyser Söze (“The Usual Suspects”)
15. Hans Landa (“Inglourious Basterds”)
14. Leatherface (“The Texas Chainsaw Massacre”)
13. Tyler Durden (“Fight Club”)
12. Pennywise (“It” franchise)
11. The Wicked Witch of the West (“The Wizard of Oz”)
10. Mr. Potter (“It’s a Wonderful Life”)
9. Norman Bates (“Psycho” franchise)
8. Alex Forrest (“Fatal Attraction”)
7. Terminator (“Terminator” franchise)
6. Amon Goeth (“Schindler’s List”)
5. The Shark (“Jaws”)
4. Hannibal Lecter (“Silence of the Lambs” franchise)
3. Anton Chigurh (“No Country For Old Men”)
2. The Joker (“The Dark Knight”)
1. Darth Vader (“Star Wars” trilogy)
although way before my time Richard Widmark in the "Kiss if Death" from 1947 is a pretty loathsome individual and the perfect example of a sociopath
https://www.youtube.com/watch?v=9DkySy18p0U