You will need to install a user script manager extension to install this script.
Ever notice that fic quality is inversely proportional to the number of tags a fic has? This script is based on Tegan's Ao3 Crossover Savior, and it hides works with too many tags.
TO USE: update the value of maxTags on line 14 with the maximum number of tags you want to see. Keep in mind that this number is count of all tags: fandoms, relationships, characters and freeform, so you may want to keep this number relatively high.
NOTE: If you use both this script and Crossover Savior or Relationship Savior, you may have to unhide a work multiple times to view it.