There's a brief mention in (very) older fluff about the Craftworlds having colonies, but I don't think that's ever been expanded on.
Since the Fall, the Eldar Craftworlds have established many colonies of their own. These colonies are not independent, but remain a part of their society, and provide troops and raw materials for the home Craftworld. Colony planets are connected to their Craftworlds by means of warp tunnels. The number of colony planets associated with a Craftworld is tremendously variable, some have hundreds while others have only one or two. Most have about a dozen. These colonies are quite distinct from the earlier phase of colonisation by Exodites prior to the fall. The Eldar Knights, as the Exodites call themselves, remain fiercely independent. Although they trade and sometimes aid the Craftworlds they conduct their societies along entirely different lines, regarding the Craftworld civilisations as being dangerously close to the old Eldar ways which led to their downfall. - White Dwarf 127
White Dwarf 127 is when they first started laying out a lot of what would later form the basis of Eldar fluff. I don't think craftworld colonies made the cut into the rest of the eldar fluff though. There is some cool potential in it though if you wanted to expand it somewhat yourself. If you think about the Fall, I'd doubt that the only people who escaped were aboard Craftworlds. You'd get a whole host of people escaping through any means possible. Little flotillas of private voidcraft smaller than craftworlds, refugees leaving on foot through the treacherous and rupturing webway. I wouldn't expect these guys would have survived too well, given the danger of the
40k universe. However, your dudes could be the descendants of some of those refugees who actually did make it to a maiden world, and against all the odds have actually survived into the present day. Not the fanatical exodites, or the ascetic craftworlders, but something else entirely
My favourite topic that actually. All the myriad options for little eldar pocket-cultures that you don't see on the big scale of things like Craftworlds and Commorragh.