To add an old Dell e1910f monitor to my setup I bought this Stellar Labs monitor mic stand adapter:
The monitor is more stable than I expected, it would take a pretty good push to tip it over. A newer, lighter LED monitor would be more stable. If you look under the adapter you can see I put a metal strip (the one you remove when adding a PCI card). I filed a curve on one end so it stays in place against the mic stand so I didn’t have to over tighten the knob. BTW, the mounting is standard VESA 100.
I had to use this adapter also: