So, this NPC is now a 3rd wizard/8th fighter/3rd wilder (psionic class). She wasn't built with optimizing in mind; I don't power game my NPCs, I try to make them based on their background stories. I'm trying to find a prestige that would really flesh her out, put all her skills to use, and make sense with her. She's chaotic neutral, a Niomus (for those of you that have the Mythic Races book) and she is geared mostly to be destructive. Any prestige classes you suggest? Or should I just have her keep going up in levels in her basic three classes?
On a more general note, where do you pull most of your prestige classes? Is there a famous website out there I don't know about, or does everyone just take mix-and-match from various books and magazines?