It's not often they create a new category of NPC, but "Aberration" has just been added in 5.1 to cover oozes, flesh beasts and tentacle things.
I haven't been very thorough in my checking, but all the ones I've seen have been set accordingly.
I wonder if Sha should belong to the same group, but for now they remain Elementals.
There doesn't seem to be a Hunter "Track Aberration" that I could see yet. I guess there'll be one eventually.