I needed a place to put my headphones that wasn't in the way, and this is what I came up with!

Low poly because it will print well on its side, which will give it the best strength.

I designed this with the 0.77 inch (19.5mm) thick desktop that I have in mind, so if your desk is a different size, scale accordingly. As long as your desk isn't too much thinner than this, you shouldn't have any issues scaling down (too thin and the headphones won't fit anymore). Scaling up I don't see any problems.

I also added a little hole for a screw to keep it from sliding along the edge of my desk, using whatever screw I had handy at the time. Could I have just drilled into the bottom of my desk? Probably. But this keeps it close to the edge.