Help identify this cabinet clip used to mount face frame on cabinet?
Hmm, those were harder to find than expected. It's extremely unlikely that you'll find an exact match (unless you can go back to the manufacturer of your cabinets), but here's a few possibilities. 

Hettich: https://diy.hettich.com/en/products/connecting-fittings/carcase-and-cabinets-connectors.html

Blum: http://www.wwhardware.com/blum-surface-mount-rta-fittings-b040-2

Lee Valley: http://www.leevalley.com/en/hardware/page.aspx?p=40080&amp;cat=3,41306,41319&amp;ap=1 (Although these don't look like much, they're extremely solid and set with a satisfying thunk. They'll also come apart without wrecking anything.)