I had been storing my filament in sealed storage bins which became frustrating having to dig them out every time I searched for a specific color. I needed a solution particular to my available space but also wanted one I could adapt for other spaces.
I came up with this modular rack. It can be stretched or stacked as tall or wide as you like using the included support braces.
It was designed for ¾ inch dowel rods but I included blanks if you choose to use a different size. If you need something other than ¾ inch simply add a negative part in the slicer and make the hole .15mm larger than the size of you dowel rod so it will fit nicely. You may want to make a test part prior to printing an entire frame piece. The vertical rods are 196mm which provides a small amount of clearance for a 200mm spool.
If you'd prefer a stronger version with less supports see my other version with triangles in the braces.
https://makerworld.com/en/models/152626#profileId-166657
#6 screws to fasten the frame to the rod. I recommend at least a 20mm or 1" screw length.
Mini caster wheels can be installed to the bottom for easy movement as desired. *If you don't use the casters look in the files for taller bottom feet to keep the spools off the ground.
I used these from Amazon. https://www.amazon.com/gp/product/B0BS287L8Q/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1
Update 1: added 3MF and stl files of all parts with solid rather than honeycomb cross pieces. You can now print upside down reducing supports significantly.
Added bottom row parts for small spools.
Update #2
Added stl's for taller bottom row. If not using caster the spools sit on the ground. Print these taller base feet instead.
Update #3 Now have parts for a metric size 24.5 and 20.3 mm dowel rod in files folder.
Update #4 No updates to these files but have created an adapter system for using small spools.
Small Spool Adapter: https://makerworld.com/en/models/192133#profileId-212217
Assembly Video