I designed this for my wife and there was a miscommunication about the spool sizes she uses but she decided to just use it anyway. Figured I'd upload it in case anyone else could benefit.

This will hold 14x of the 2" tall by 1.5" diameter spools or as many smaller ones as you want to cram in. I've also included the Fusion360 project file if you want to tweak it to your needs. The overall footprint is 200mm wide by 181.5mm long and 63mm tall (7.9" x 7.15" x 2.5").