The D&D girls. (Sailor Moon)
Seifer (FFVII (He can kinda count as a villain, right? XD)
Organization XIII (Kingdom Hearts, Cheyah!)
Rita and Lord Zed (Mighty Morphin PR, XD)
Voldemort, and the Death Eaters (Harry Potter)
Wow, there are alot, so I might be posting multiple times in this thread. XD