Valence Clips for Blinds
They're just called &quot;valence clips&quot;, but that likely varies by manufacturer. They're proprietary, so you'll either need to contact the manufacturer or do some trial-and-error with parts from other vendors. Chances are they'll often fit the valence, but they may not fit the blind channel as well.
You could also just use double-stick foam tape, self-adhesive hook-and-loop strips, or anything similar.