I'm trying to identify some connectors for a Chevy Equinox, located on the rear mud flap. I believe these are common GM connectors but I do not know the nomenclature.
The second image shows a U-nut,speed nut or clip nut depending on the manufacturer. They are available at most auto parts suppliers. They are available in a variety of thread sizes and the length of the clip also varies with application. The easiest means of selecting the correct size is to remove one and match it at the store.