Zaheer because I find his beliefs fascinating and he almost comes off as heroic.

Too many

Belos due to his real world influence

M-OC from Freemaker Adventures is cool.

I’ve always loved the original Skeletor. One of my all time favorite villains (nostalgia)

Invader Zim (he’s incredibly evil and stupid at the same time, I love it), Ren Höek (I love insane characters, what more can I say?), and Scratch and Grounder (goofy evil robots, ‘nuff said).

These ones aren’t really from a show, but a game. But the Cogs from Toontown are so enjoyable and lovable, I can’t help but smile happily on the inside. Corporate Clash managed to extend this amazingly, though most of the managers in the server aren’t really evil at all.