The V1 pin I designed works OK, but when I've tried to use it with new shelving (especially with cheap shelving) the pin and shelf size seems to vary from manufacturer to manufacture. A parametric design would make printing out a new set of brackets easier.
I developed an OpenSCAD version of the shelf pin, and made it parametric in design so that one can easily adapt the part for thinner or thicker shelves or mounting holes/pins.
The design works well in OpenSCAD - it does not, however, currently work in Thingiverse's Customizer, because that service is currently broken (and unfortunately has been for several weeks now). The .scad file is attached here for others to use - I hope you find it useful.
I was looking specifically for a shelf clip in OpenSCAD, so thanks for making this! I needed a shorter (3mm) pin and also I needed it to be much wider than usual to compensate for a too-short shelf, but it was easy to adjust those. Great project!