agg-kicad is my collection of KiCAD libraries, footprints, and scripts. Many parts have also been contributed by other users and carefully checked before inclusion.
Most of the libraries and footprints are programmatically generated from a simple text-based description, allowing quicker and easier validation that pins and footprints are correct. When I started the project, the built-in KiCAD libraries were of quite variable quality and inconsistent, and it was hard to know which parts to trust, so it made sense to roll my own. These days the built-in libraries are high quality and much more consistent, so I’d probably use them instead if I was starting over.
All of my personal KiCAD projects use exclusively parts from this library.
Useful scripts include stickerbom, which generates printable sticky labels for each line in a board’s BOM, showing where on the PCB a specific part needs to be placed, allowing easy hand assembly away from a computer.
Stickerbom on hackaday.