I needed some shelf pins to fit ¼-inch holes in a bookshelf I built, and decided to work on my FreeCAD skills and design my own. This design is based on an old plastic shelf pin I had in my shop, which had the wrong size pin and a smaller gusset, so this one should be stronger. I printed them using some brown PLA and they worked perfectly.

I'm including the FreeCAD file in case someone wants to remix it. I didn't bother making it parametric because I probably won't need any more of these any time soon, but the dimensions should be easy enough to modify as needed.