I see my little Tulare decal is in good company. In California, each of the 58 counties has its own Agricultural Commissioner or Sealer, so there would be 58 different stickers to collect. To my knowledge, nobody has ever done so. They would probably show the county seal of each place.

I'll keep an eye open for any in flea markets, or any falling off gas pumps but that doesn't happen very often. I take it, only the actual seal interests you? As opposed to photos of them which would be easier to take!