I wanted to mount a monitor on a laptop desk mount, so designed a VESA adapter for it.
The desk mount is the ThingyClub Adjustable Aluminium Universal Desk Mount which can be found on Amazon.
Model is available via onshape: https://cad.onshape.com/documents/968f6e076eb098469403b7eb/w/1ad75bde1971097c49991ebf/e/52d7734a5a0b48eb0879a42f
You will need 4x 10mm M4 countersunk screws.