It appears that a lot of people are migrating to Facebook Marketplace to sell their Bronco so I've created a site to find Ford Broncos across Facebook Marketplace among other sites... and I thought it would be of interest here:
https://cultcars.us/cgi-bin/listings.cgi?q=1966-1977+ford+bronco
https://cultcars.us/cgi-bin/listings.cgi?q=1966-1977+ford+bronco