Camera Tripod spare quick release plate / shoe - 1/4"-20
Spare tripod / Camera mount shoes.
1/4"-20 screws can be found here
https://www.amazon.com/gp/product/B07F74FXXB/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Drill the screw hole to size with a step drill (made small on purpose).
Fusion 360 design:
https://a360.co/2Omt3N7
Edit: Increased the step diameter to accommodate larger fold-out handles