User blog comment:Sirin of the Void/Your Top 10 Most Vile Villains from Villains Wiki/@comment-32583560-20191130182901

No particular order:

1: Makuta Teridax from BIONICLE

2: Fabius Bile from Warhammer 40,000

3: Crayak from Animorphs

4: Emperor Palpatine from Star Wars

5: SCP-4666 from SCP Foundation

6: Isaac Ray Peram Wescott from Date A Live

7: Unicron from Transformers

8: Angra Mainyu/Ahriman from Zorostrain mythology

9: Evolt from Kamen Rider Build

10: Vilgax from Ben 10

Although in terms of work familliarity, I'm only really familliar with Palpatine, Unicron and Vilgax, but I read about how the rest of these are and they're awful