This set of web pages explores the swatches that come with F6 plus the add-on swatch pack that adds 50 odd more.
These swatches can theoretically be used with any theme, not just Foundation 6
The main swatch that got me going is the background swatch, used to produce fixed bacgrounds that could have scrolling content. It was explained to me in Joe's January 19, 2024 Hangoutl..