I have used Ground Zero Games' SG15-HW1 generic heavy weapon crew in field caps as civilians. They're the sort you often see working around a starport moving goods about the place. Safety is important, note that the chap on the right is wearing his steel toecap boots!
They've been painted in the usual mix of Vallejo, GW and Humbrol acrylics, shaded with Vallejo sepia ink.
They'll mix well with my other GZG civilians/colonists. I have some more to paint, I might try a couple of head swaps with them to add some variety.