I saw Autofire's game, but he's programming in a language I'm not experienced in, and I've got a specific direction for my game which I'm not even sure FFL supports. (I have absolutely zero need for a level editor as my game's world both generates and reconfigures itself procedually and in real time)

If Compound 42 or Ghost in the Machine are on the current list of danger missions, they'd be pretty awesome for screenshots. (I'm not sure if the latter has anything not already in a Power Complex though)
Compounds in general, actually, have a couple interesting setpieces IIRC. Ironclaw Munitions Factory, Operation Crimson Hammer, the Maskeraith Battle Sprite mission (which goes through the Gremlin complex, right?) and the Collector mission are all good candidates. If there's anything worth taking a screenshot in Emberlight, do that too.

Honestly, pretty much anything bigger than a box and that isn't destructible is nice, I'm even studying things like the wall tiles and such. They're all in the files so I can Spiral Spy them, but a lot of them have no context or need to have their textures found and applied so it's often far easier just to see an ingame screenshot of them.

Currently I'm just using 2-minute scribbles in paint of machinery I think the Clockworks would need for functionality. If there's a Clockworks equivalant, I'll change the sprite to that. If there isn't, I'll redo the sprite in the style of similar machines.

Thanks in advance :)

Thanks, a couple of those images are good references or reminded me to look up the following things:
The grave found in Blades of the Fallen
The equipment and props found in The Ready Room/Mission Lobby
The large lichen meteorite
The storage rooms in Deconstruction Zones