I'm sure this has been discussed before and I know it would be a huge task to implement it on posts on this site, but what are the feelings on a tag for canon characters?

I'm sure one of the big hurdles is to ask what would qualify as a "canon_character", so I would set the description as this: "official licensed characters from established franchises and series." Meaning that posts only get the tag if features a character from a franchise, series, or entertainment company (i.e. Disney characters). This would eliminate all fan characters and fursonas from the image search, essentially giving e621 a "Rule 34" mode. Could even have a "Rule_64" tag implication to go with it.