MBot Raftless Spool Holder
This is a variation on the Mbot spool holder. I made my own before, but some of my spools were a little wider and would fall off. I liked the ridges on this one because it can accept varying spool widths. The original took a long time printing support material, so I trimmed one side flat so it can be printed without support material.
Print and enjoy. I think it has a flap to reduce stress on the hole in the panel. If this is so, you could mirror it for the other side. The one I created myself didn't have any I was using it fine for a long time.