There's a few NPC who were not upgraded yet :
-Centaurs who can still be upgraded in a barrens Warfront
-A lot of beast from the Barrens (lion, giraffe) who can still be upgraded in a barrens Warfront
-Gnoll who, I am pretty sure, can be upgraded for a Dragon Island patch as they're the perfect filler monster with kobold and murloc
-Swampthings who can also be upgraded in a Green Dragonflight wing of the island
-Some vanilla beasts like wolves and boars who were replaced by their WoD counterpart
-A few scourge really specific monsters like the bone skeletons (Rattlegore) and the wight (Stalagg and Feugen)
-Dragons, almost all of them (whelp were upgraded with Legion)
I guess we'll have an answer soon anyway. 8.2.5 do not looks like a big update and don't bring an allied race so I guess we can expect it for early / mid september and 2 or 3 weeks after its release we'll have the 8.3 showcase with Jeremy Feasel and PTR next week.