Here is a headphone holder I made. It is nicely robust and very easy to print. I tried to make it fit the aesthetic of my other thing, the Xbox One Controller Stand.
It may be too big to print for many printers, so here are the dimensions: 230mm x 200mm.
If desired, I can make the holder size a little smaller to accommodate printers with smaller build areas than my CR10, like the Ender 3. Just give me the dimensions you'd like and I'll add the STL files.