Made a cap for VIVO Monitor stand that also has 1/4-20 mount. Inside dimensions are 35.5 mm wide and 21mm deep.
Made to fit this Monitor Stand: https://www.amazon.com/dp/B00FOTABWY/
Used these ¼-20 screws: https://www.amazon.com/dp/B08R7TWF32
Source on OnShape: https://cad.onshape.com/documents/562a29d9d5b604a3a4f16f21/w/979541bedc7b94f052920cb4/e/cccb4338a90c930bfba17733?renderMode=0&uiState=63d7173cb8df1903dbbfa867
The author marked this model as their own original creation.