A wiki page for deprecated mouth tag has a long see also list.
Which plan would you think the best? 1. Move the list to tag group:face tags 2. Create a new tag group for mouth (Am I able to do this?) 3. Just keep as it is (because it is intended)
I would keep the links to mouth focus, parted lips and the face tags tag group and just remove everything else.
That's make sense. I have found some mouth tags under Drawing styles section of tag group:face tags. If somebody want to add some more mouth tags to the list, they would put them under there.