There's been a slight misconception in here about what alternate reality means. Parallels, Remember Me, & Yesterday's Enterprise are really the only true alternate reality TNG episodes. Although Time Squared has elements of alternate reality in it
The Inner Light, Frame of Mind, Eye Of The Beholder, Interface, The Mind's Eye, & The Battle, are all either set in or contain elements of existing in an altered mind state. Dark Page, Night Terrors, Violations, & perhaps Phantasms could also be categorized that way
Future Imperfect, & most Q episodes like Qpid, Hide & Q, All Good Things... & especially Tapestry are all debatable, because there's the illusion of plains of existence occurring, but it's realness is subject to question, based on the powers of those creating it. For all we know, Future Imperfect is really just an episode centering around a very intuitive holodeck type phenomena, & Tapestry might just be Picard having an "It's a Wonderful Life" dream, & even if it is a Q creation, how real it is we don't know.
Where No One Has Gone Before is open to debate too. That's a stumper, because there's verifiable divergences occurring in reality, but their realness is questionable