They are normally used for holding the wheel arch lining in place. Plastic Nuts for Wheel Arch Liners.
10X Wheel Arch Liner Splashguard Clips Nut For Hyundai Elantra Tucson Santa Fe
10x WHEEL ARCH LINER SPLASH GUARD TRIM CLIPS UNDERTRAY FOR CITROEN C3 C4 DS4 DS3
10x VW Wheel Arch Liner Splash Guard Hex Nut Large Audi Seat Skoda WHT000713
10x Vauxhall Corsa & Tigra Front Wheel Arch Liner Clips- Inner Wing Splashguard