For google you can use this https://addons.mozilla.org/en-US/firefox/addon/g-search-filter/ https://addons.mozilla.org/en-US/firefox/addon/g-search-filt..., jus

For google you can use this https://addons.mozilla.org/en-US/firefox/addon/g-search-filter/ https://addons.mozilla.org/en-US/firefox/addon/g-search-filt..., just drop in your list of those 500 URLs, once you've decided on what the top 500 is. For other engines you can use https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/ https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/ with this script https://greasyfork.org/en/scripts/1682-google-hit-hider-by-domain-search-filter-block-sites https://greasyfork.org/en/scripts/1682-google-hit-hider-by-d...