I’d say my favorite villain of this type is Emperor Palpatine. No ‘greater need’ motivation, no redeeming personal qualities, nothing to sympathize with- just sheer sollipsism. When you get down to it that’s all Sith philosophy is- the idea that everything and everyone in the galaxy is just there for the whims of whoever can exercise the most control over the Force- and in my opinion that’s what makes it effective as a Religion of Evil.
Speaking of sympathy, I am kinda fond of some stories where a Pure Evil villain is shown in an initially sympathetic light- only to start punting small animals as soon as it’s even vaguely convenient/the other characters aren’t watching. Maybe it’s just the whiplash, but I enjoy that. One example: Lex Luthor, whose villainous career revolves around a very well-maintained public persona. Check out Lex Luthor: Man of Steel for a great example.