If you have never read Schmitz's The Universe Against Her (1964), I have very fond memories of its teenage protagonist Telzey Amberdon and her relationship with large invisible cats. And on that note I also recommend Vinge's Psion, Catspaw, Dreamfall, although they read (like Doris Egan's Ivory books) like an open-ended series that someone abruptly put the kibosh on. There's a novella, "Psiren," that takes place between the first two novels, but I've never seen anything post-Dreamfall.