Just a quick design for folks like me who prefer their stuff vertical. The default size is for A4 paper/magazines, I've also included one that will fit filament spools. Note that this does take quite a bit of filament when it's large (photo is of a ⅕ size filament spool holder). You could adjust this to hold other things, too, but it's just a simple flat design so there are probably more useful designs out there.