I use OpenSCAD for all my 3D designs. I recently discovered that there is a standard(ish) format for publishing a design that creates a user-interface of adjustable parameters. This allows anyone to generate a custom STL file without having to know anything about OpenSCAD (or 3D design).

I needed a control-arm for a project anyway, so I created a parameterized design:

https://www.thingiverse.com/thing:3979363

Oops ... edited ... mistaken identity