Whiteboard Organizer

This holds 6 markers up to 20mm diameter, and one eraser 52x30mm.

I made a version that can clip on to a 1x3" (19mm x 39mm) frame with no supports, and one that will allow you to glue 8mm magnets or use double-sided mounting tape to attach to the whiteboard. (also needs no supports.) All angles are 45 degrees and should print on most printers with no supports just fine. 

For the magnetic version, simply print in the normal orientation. 

For the clip version, stand on edge, where the clip and marker corner align to the build plate. Use a large brim for good adhesion.