I mounted my thunderbolt hub on the underside of my desk, but needed a few more ports so I added a usb C hub. I created this to mount it next to the thunderbolt hub. I added room for 6 screws, but it seems to be stable with only two diagonal screws. The hub I purchased had USB C , but I can't find that on their website any more. However, they do have what appears to be a USB A version of the same hub. I have not purchased this version, but it does appear to be exactly the same so it would probably work.

https://www.microcenter.com/product/640952/inland-4-port-usb-30-hub