Télécharger Block or Highlight Search Engine Results pour Firefox. Filter your search engine results. Block unwanted results and highlight the favorite ones. It works with Duckduckgo, Google, Yahoo, Bing, Startpage, Ecosia, Yandex, OneSearch and Baidu. https://youtu.be/U_Ctx4Gq-lw
Looks useful to hide sites where you have to choose between accepting targeted ads and paying a subscription.