My Logitech c920 Webcam used to sit on top of my monitor, but when I replaced the monitor with one that had a smaller bezel the camera would actually cover parts of the screen, so I decided to design a mount that would let me attach it to the middle of the ~$30 ring light that I have above my monitor.
This is is designed to fit this ring light, but could probably be modified to fit others with minimal changes. I included it in .OBJ also in case that makes it easier for people to customize.
It was designed to interface with Felwat's c920 mounting adapter with a 30mm M4 bolt and M4 nut to hold it snug.