>>10317200There are some vinyl items, like the Banimon tank, the Onell ship parts, and I think some of the other large vinyl figures can be taken apart and used as mech suits. I know there are official wheel joint sets, but it looks like they haven't been sold in a while.
You're probably better off using Star Wars, Playmobil, Lego, Megabloks, Imaginenext, old Fisher Price, Lanard, or the cheap walmart brand box sets if you're looking for playsets and vehicles.
The brand TimMee is still making that plastic mountain that was packed with army men, dinos, and the lot for years and years.
https://www.amazon.com/TimMee-Battle-Mountain-Scenery-Display/dp/B0B7P55VC8/ref=sr_1_4?keywords=Tim+Mee+Toy&qid=1678412654&sr=8-4They also got this really cool generic fortress that's 3 3/4 scale, but it's $125
https://www.amazon.com/dp/B099D5YM64/?coliid=I216FWE2IKSLJV&colid=2ENCW3WHDU6DE&psc=1&ref_=gv_ov_lig_pi_dpMichaels has a blank wooden castle you can decorate yourself for about $25 in the wood section. One anon did one up real nice for his pose skeletons years ago.
Could always just make something of your own if you feel crafty.