This is a minimalistic spool shelf and a relative small print, which should fit on any 220x220 sized printer.

You simply stack filament spools with this shelf rim in between. The holes, usually used to fixate the filament on the spool, are used to screw the spools together and create a multi level shelf for your desk or workbench.

I use the stacks to hold my de-soldering and my hot air station on top. The shelf's below keep the accessories, tools and replacement parts. 

The created shelf is very stable. If your spool only has one set of holes, you probably need to create an additional set on the other side to avoid creating a Spring-O.

The FreeCAD source file is included. Just open it with FreeCAD and select the Spreadsheet, where you can specify diameter or the spools and the screw hole size and spacing. So the shelf can be used for any spool size. By default there are holes for 3mm bolts, which secure the spools together.