"Let's see... there's the Keys Collated and Revised, in seven volumes, for a general introduction. The most comprehensive available source on vampires is simply titled Vampyr, but its unofficial title is the Leaden Brick for reasons that I'm sure will become obvious the first time you try to pick it up. Magic-eaters, mirror-walkers, and several varieties of usurper all appear in Journeys of the Damned. Demons who possess or command under unusual conditions are the main subject of Goetia Esoterica. I think that's everything I mentioned. Oh, and the Fyarl have their own page in Twelve Hundred Demonic Mercenaries, which contains only one thousand and fifty-eight species."