I've got a boat load of Prodos marines & aliens (plus a couple of predators...), so I got more than enough of those. I participated in their KS way back, and it was really difficult to get them deliver my pledge... but they did, eventually.
I have the miniature game rules box too, so I have the floorplan tiles which are fairly usable, although some graphics are a bit odd.
Floorplan wise, I also have the old GW Space Hulk tiles, and the Sulaco resin tiles from Fenris. Ideally, I'd need some special rooms and furniture maybe.
In minis, Colony 87 has some usable minis, although some of them are a bit 'grim dark' ie. 40k, but there's some mechanics there. Likewise, Heresy Miniatures does a set of 'inspectors' wearing uniforms/coveralls which should be easy to paint as space truckers etc. Statuesque Minis has a repair crew, mechanics in coveralls. They're bit borderline pulp/scifi but should work great.
I am looking into the possibility of printing some minis of my own, I Got a 3D printer from black friday offers. I expect the quality won't be anywhere near commercial, but we'll see. You can get both free and commercial STL files (for printing), anything from Sulaco/Nostromo craft, to M577 and Cheyenne Dropship, and neomorphs, characters in spacesuits etc. Not to mention all sorts of floor plan tiles etc. So there's quite a lot to go on.
It's hard to keep up with all the kickstarters going on, but I noticed Battlesystems has newish Core Space boardgame with minis and 3d cardboard terrain. Most of the humans look pretty interesting, the various aliens are less useful.