Recent changes to the Legion mounts database, some have been mentioned previously but I'm consolidating them here:
Six "Prestigious" mounts have been removed from the database listing. Presumably they decided they had too many at launch and want to save them for slow release. Hopefully they'll reappear in later patches :
This leaves two Prestige mounts at launch : the
Prestigious Ivory Courser and
Prestigious Bronze Courser.
The so-called "Fel Bat (Test)" mount has been removed too, which isn't too surprising, given its name. I had hopes that they might give it a proper name once they were happy with it, but it seems that they decided to scrap it for now, meaning the fel bat model is unlikely to be available as a mount, in any colour, at launch.
The Great Northern Elderhorn is a second Leatherworking mount. It's the brown one, but one point of confusion is that it was assigned an icon for a white moose mount. In fact they created and added the white moose mount icon just recently, seemingly for it. Maybe it'll change appearances yet, or maybe they simply changed their minds.
As noted before,
the Arcadian War Turtle is no longer listed as a Blacksmithing mount, but as being sold by Xur'ios in Dalaran. He's the guy that also sells the Eng. recipe for the item to allow hunters to tame mechanicals. However, (i) he doesn't actually sell the mount in the Beta, yet and (ii) his specialty is crafting recipes, meaning it's still possible he will sell the Blacksmithing plans rather than the mount and the current database info is not quite accurate. We'll have to wait and see.
The Fel Core Hound was renamed the Steelbound Devourer, but has not otherwise changed.
The Vicious War Elekk received flavour text.
Unless I miscounted, I think that means the new tally is 26 mounts in total. 16 from non-PvP sources and 10 from PvP. Of note, I don't think there's a single case of "earn reputation and buy a mount" listed for this expansion, which is unusual. :/