After seeing some similar filament storage solutions online, I came up with my own shelf bracket for getting my growing filament collection organized. Brackets use standard 1x2 lumber for the rails of the shelf and can hold filament in or out of boxes. Since I installed these on a studded wall with no drywall I added a raised 1x2 location in the back for a stop when storing boxes. I didn't do any strength testing, but utilized a bracket on each stud for the maximum strength and it seems quite solid.
After printing a bunch of brackets, I thought it would look good to make one in the pacman color scheme. So I added some printable inserts for each of the cutouts, you may need to adjust the scale of the inserts for your printer to get a good fit.