I wanted to model out the shelving we used in our warehouse for a project. It's simple, and mostly to scale. Each millimeter is equivalent to an inch. The horizontal file is a 10 foot section, but can easily be scaled in your slicer to whatever size you need. I'm printing these out and gluing them together, so I will upload the files for those tools when I make sure they work.
This style shelving has keyholes facing outwards on the vertical pieces and flanges with pins on the horizontal pieces. I skipped modeling the flanges on the horizontal pieces to keep it simple. Besides, that wouldn't physically work when printed at this scale. You can use these models to help plan out warehouse shelving if you need to do that. Trust me, a little computer work is a lot easier than moving these things.