I’d like to get a resin printer someday. I print in PLA right now. A nice trick I’ve found printing things for my locomotives: you can buy PLA filament that is 40% iron filings. It prints with a nice texture that hides layer lines. The grey naturally matches grey undercarriages. And bonus: if you put it in a saltwater bath for a few days, it will actually rust!
I would be extremely interested in this stuff. I'll search for some but do you know who makes it?