Setting considerations probably need to be taken into account. Anything not human and Netherese would either be considered fit only for slave stock or extermination. Half-breed races that could pass for pure human, close up, would probably integrate the most easily, though they would have to be careful about who they revealed their nature to.
Of course, standard races have this problem too. I play a half-elf and a gnome, for example. The half-elf is acutely aware he will always be nothing more than a second class citizen. And the gnome is a former slave of a Netherese archmage who has no illusions about some other wizard enslaving him again, if the whim takes them (although, my gnome is batshit crazy and isn't particularly bothered by the prospect.
).
On the other hand, extremely powerfully gifted extraplanar species might be able to garner enough respect to visit an Enclave if they mind their manners and the high-magic nature of the setting means there could be lots of exotic species owned by the Netherese as slaves. This particular era of Faerun is one in which seeing bizarre creatures on the streets could actually make sense.
I would say throw whatever you want in there, just make sure to add RP guidelines on how you think the species would be perceived and integrate into Netherese society.