This is one of the workholding solutions I use on my CNC machine, which uses a lever with a CAM to tightly clamp onto the edge of a part. To mount these pieces, you’ll want to drill & tap your wasteboard with 1/4-20 holes at 1” spacing (fairly standard!) and then I use nylon 1/4-20 button-head screws for mounting (to prevent tool breakage.)
This system is cheap, flexible, quick to make, works reasonably well, and clamps & unclamps quickly for production.
You can also use multiple of these clamps for additional stability if you are dealing with larger side-loads. I recommend printing these pieces with 100% infill.