Sorry, I wasn’t very clear with my reply. I haven’t actually found an app that does this kind of thing very well, just yet. My reply was more in the line of “I wish I had an app to do this, because searching the internet takes forever”.
Some brief searching came up nowhere when I went looking a few hours ago. I did find two apps on Google Play that seemed like they might work, but both had their own blend of issues, and neither was on f-droid, unfortunately. They were “No Thanks” and “Boycott X”, if you want to try them out.