You’ve got some great stuff, especially the vehicle stowage! (and I do love the moooo cow! cracked me up!)
Sci-fi: as said above, HVAC units, power generators, solar panels, “techie-bits”, moisture collectors, futuristic antennas, information kiosks, vend-o-matics, automated gun turrets… I do like the ideas of various doors and windows in order to make buildings, but they would have to be awful slim which would make them difficult to caste.
Modern: bus stop benches and shelters, vending machines, dumpsters, hescos, street lights, traffic lights, gas station pumps, cars, crushed cars, mailboxes (boxy US type and cylindrical UK types), garbage piles/scrap yard rubbish
pre-modern: market stalls, siege engines, and that’s all I’ve got for that!
"I saw this in a cartoon once, but I'm pretty sure I can do it..."