Does what it says on the tin. As AO3 annoyingly does not let you set a blacklist so this add-on is essential (alongside "AO3 Enhancements") to not have finding new fics be a chore.

Amazing, I am using it with the AO3 Enhancements Options (Because AO3 EO doesn't work for fandoms and characters when you want to block them as well)

had some trouble getting this to work at first, but I was able to overcome the issues and am happy to report that it runs smoothly. now I dont have to Witness Horrors and be horribly triggered every time I go into a tag! Thank you!

Thank you for letting me permanently block that one annoying million words and two million tags fic from ever appearing in my search results again. Works like a charm.

Great for avoiding triggering material (csa/noncon/ect.). The interface takes some getting used to but is pretty easy once you get a hang of it.
Only problems I've encountered come with removing usernames from the list of blocked things. Would be great if an option for that came because I accidentally put in two usernames at once and effectively broke the app lol.