https://www.amazon.com/gp/product/B001YI12A4/
I've had a 3U one of those for years and used it pretty much exactly for that. As long as your desk is wide enough and the stuff isn't too heavy, it works well. They're not weight-rated for use under a desk, just for mounting on a wall. So, you kind have to just guess at the weight and take your chances. I wouldn't put anything with transformers or a heavy power supply in it.
You will smash your knee into it at some point. Don't say I didn't warn you.