That's a good idea but there are some issues that prevent it from being practical. Danbooru and Sankaku Complex have a limit to the number of tags you can use at once (2 and 4, respectively). It takes more than that just to weed out unsuitable file formats, sort by popularity, etc. Even if that were solved, there'd still be the issue of duplicates, which is a solvable problem but would take quite a bit more effort than I'd like to invest at this point as I'm not really actively developing the project anymore. Sorry orz.