Requested feature overview description.
Tags that convey technical data and information not present in the visuals of a post, such as highres/absurdres, story_in_description and alternate_version_at_source would receive a new category like the ones already in place for artist, character and copyright tags.

Why would it be useful?
It makes it easier to pick these tags out of the general tags. This would be helpful for noticing request tags such as character_request and source_request, or for translators when adding/removing translation tags.
It may also stop some improper tagging - users who use some of these tags for visual aspects of posts may notice the new category and realise their mistake.

What part(s) of the site page(s) are affected?
Tag lists

I'm almost certain this has already been proposed (along with some discussion of other potential tag categories). That said, the thread seems a bit hard to find.

Previously suggested tag categories: color, gender, lore, medium or media, character basics and background detail

+1 but the admins have said this is difficult to implement.