Patio Stone Gap-Fillers for Zone 6

This question is similar to the one posed by the two folks from Alaska in 2002, but this is a West Virginia, USA climate and a different sort of patio. I would like to grow herbs from seed that can tolerate shallow soil and foot traffic, and will be relatively soft to walk on, and low. Any suggestions?
I love your site, too! What a wonderful source. I hope to be purchasing seed from you soon.

Creeping thyme and wild thyme should be hardy enough to fill the cracks between your patio stones. Make sure you water them well the first year to allow them to get established. If you have any deeper pockets of soil, start your plants there. They will spread and still be able to get water from the portion rooted in the deeper soil. There are of course some invasive plants that might be just the thing if the thymes fail after all. Creeping Jenny comes to mind as a low plant.