These are a bit ugly, but they worked for my purpose just fine so I'm uploading them in case they help someone out. You can flip them over for thin or thick material.
There are two components. If you make the triangular pieces shorter or taller you can better secure your particular thickness of material.
I'm using them with dovetail hardware: 50mm M5 screws https://www.printables.com/model/727936-microjig-matchfit-dovetail-fixture-bits-knobs
Shown securing 1.5" (2x4) for cutting at angles.
The author marked this model as their own original creation.