src/files/social-icons: https://simpleicons.org/
src/files/theme-switch: https://icons.getbootstrap.com/
faces.js: copied from https://dumbmatter.com/facesjs/build/bundle.js
Minified JS: https://try.terser.org/ and checked in
https://basketball-gm.com/, https://football-gm.com/, and https://zengm.com/ are actually just one big website generated by Eleventy.
JavaScript
src/files/social-icons: https://simpleicons.org/
src/files/theme-switch: https://icons.getbootstrap.com/
faces.js: copied from https://dumbmatter.com/facesjs/build/bundle.js
Minified JS: https://try.terser.org/ and checked in