I've been tagging grimdark for uploads that are less sunshiney than the typical user might want to look at. I considered just dark but it appears some folks have used it to describe colors of characters or the lighting a scene and wasn't sure about grim.
Grim is basically unused at the moment and might be less ambiguous than 'dark' and more guessable than 'grimdark' (which is sortof a more recent thing).
If we took this I'd probably ask for
alias: grimdark -> grim or dark_theme (has 71)
and maybe
alias: dark -> dim (has 3 posts) or dim_lighting (has 1 post) or dimly_lit (has 0 posts)?
There's a few pages of stuff that I'd be willing to go through and make corrections to, followed by adding a wiki-entry so things stay tidy better. Does that proposition seem about right to everyone? Tweaks?
Updated