Master Mount by Elgato
If you're looking for a way to mount a camera or a light on your desk, the Master Mount by Elgato is the right place to start. It's adjustable, sturdy, well made, and pretty much everything you need from a desk mount.
I've used this mount for video calls, for lighting setups, and more recently, when combined with the Elgato Flex Arm, for my overhead camera rig (perfect for my flatlay shots!). It's adjustable in height (from 22-49") and comes fitted with a ball head and 1/4 inch screw that is compatible with all standard cameras. Best of all, it attaches to my desk with a padded c-clamp so it takes up no space at all.
Elgato's Multi Mount System was originally made for professional streamers, so you know the gear is legit. There are also a handful of accessories you can add if you need to deck out your setup even more.