Theo Galavan from Gotham

Aunt Marge

Also Ridley (especially in the manga)

Judge Claude Frollo.

I actually found Frollo pretty cool, but i do understand your answer.

Ramsay Bolton and Brian Irons. Both of them are extremely misopedistic sick f**ks.

I so understand why people liked Frollo as Hellfire was a pretty good song. The Coachman is another good candidate.

The Coachman is a good answer, while Frollo was pretty cool, The Coachman was just nasty.

Bayaz, the main villain from The First Law trilogy. He is not very famous but he is nonetheless one of the most hated villains in the fantasy community. He is actually a more effective hate sink than Joffrey and Umbridge because they are presented as hateable characters from the very beginning. Meanwhile, Bayaz is actually presented as a good guy at first but then you learn that it is just a facade and he is just a manipulative sociopath who cares only about his own interests. Plus, he won at the end of the series and received no punishment for his actions unlike many of the other examples that are listed here which makes him even more hateable.

Micah bell tbh

Hell yeah good answer, my first edit (as i remembered) was that i added on his trivia that he was the most hated Rockstar character (and he is).