Fall-From-Grace, a redeemed succubus (IIRC she's CN), is from the Planescape: Torment computer game. She also appears in the Torment novel, and has her stats given in Dragon #264.
Also, A balor named Raachaak, and three vrocks named Shaakat, Rejik, and Morbaat appear in The Paladins, by James M. Ward and Davis Wise, book two of the Forgotten Realms's infamous Double Diamond Triangle Saga. The three vrocks are all dead by the end of the book, but I don't recall offhand whether or not Raachaak appears in the later novels, or what happens to him.