| Garretmander |
I'd say robots followed by undead, if you don't consider ghouls of different races different.
Then the 'swarm', probably the most populous entity in the galaxy, but made of all sorts of subraces.
After that? Probably humans. Azlanti humans specifically, with vesk a close second, they are the only races with large numbers of planets they have conquered and colonized and settled with just themselves.
Unless there are others yet to be discovered in the vast.