Simple clamp I made in Fusion 360. Fusion file included, with user parameters for most of the stuff. You can make the “legs” two different lengths, just change Width and Height parameters.

DXF's in 3 sizes: 75x75 S,  150x150 L (pictured), 200x200 XL

.STL in 150x150 just in case you wanted to print this ¾" thick.

Note, in the picture, I set the slots to 8mm, but in this final design, they're 7mm which fits the pocket hole screw better.