Simple wall mounted filament shelf. Added seigaiha pattern to make it stand out a little and just for personal preference. The inner pattern can hold itself inside the holder but you can use some glue to keep it in place. 

Assembly that is mounted on my wall uses aluminium pipes with length of 100cm and nicely fits 14 normal sized spools, as you can see on the photo it also can hold some smaller ones. 
 

Assembly

Assembled with 2 pipes or rods that have 10mm outer diameter. 
Wall mounting is made with two 6x30mm dowels and two 5x30mm screws per part.
You need at least two holder pieces to safely mount it on the wall and you need to print more if you want to store more than 7-8 spools on the same assembly.

Printing

The inner pattern doesn't do anything practical so you can print it however you want, for example use bigger nozzle to print it faster or just use higher layer height. Also make sure that your bed is leveled because this pattern can be hard to print. 

Printed with Fiberlogy Easy Pla patel mint and Polymaker PolyTerra PLA lavender purple with these print settings:

nozzle - 0.4mm

layer height - 0.2 mm

infill - 15% gyroid 

permieters - 3 / You can add more if you want to make it stronger 

What's next?

I also plan to make some printable labels to organize it and maybe create some sort of holder with bearings to allow me to print from this holder without taking the spool off.