Dennis, great idea! I am onside 100 percent. Got my Elegoo resin printer about 2 months ago and have been having a blast making mostly scenic parts so far. I have two related threads running in the Scenery category here on the forum.
Most of the items I have printed were downloaded from Thingiverse, and started out as HO, G, 28mm, or 1:10 .stl files. Elegoo's slicer software allows you to scale up or down in all 3 axis, or only one. Its not perfect, but the results are generally pretty good. I have also had good success printing most objects flat on the build platform, without the need for rafts and support fingers.
I have been pushing for repository site for 3d files and your plan looks like a great idea. Happy to share any files that I have.