Exodus Fleet
A ragtag assemblage of cobbled together ships, flown by members of various species displaced, and in some cases created by, human terraforming. There are several million ships, nearly forty thousand of which would be considered capital class military vessels, housing billions of travelers ranging from Space Shuttle scale craft up to moon sized worldships. Buster hails from here, and her immediate family, as well as nearly all of her species, all live on ships within the fleet.
The fleet moves constantly and are considered a nuisance in civilized space, as the members of which consider any ship they claim to be theirs regardless of who else tries to hold claim over it. legal or otherwise. as such they're viewed as scavengers at best, and pirates at worst. they'll arrive in a system, harvest what they need, usually from any asteroids or unclaimed moons in the system, salvage any wrecks or abandoned structures, and leave. if you make an enemy of them, expect to find the fringes of your space being raided in hit and run attacks every time it's left unguarded until it's picked clean.