I have a 2020 rail CNC device that needed anchoring to a wooden platform. I looked^2 on ThingiVerse for what I needed to no avail.
After using literally my favorite software of all time, Fusion 360, and some calipers, I whipped up a 2020 screw down anchor plate.
Now you can screw down your rails to keep 'em from going off the crazy train.
GPL's by 3D Possible ; Like and post your makes.
No supports needed; Print on edge,
Position the rounded protrusions downward for the low draft angle towards the bed.
I used some calipers to measure off an existing 2020 corner bracket. I then sketched a little thumbnail and added the dims. Open up Fusion 360, and draw the parts, entering the dims as you go. Combine bodies if necessary., render to STL, then slice to GCODE.