Forget star signs, what AO3 sign are you? I am T-gen-no archive warnings apply-complete.
Sometimes G if Sam and Dean are just sitting around and sometimes M, generally if terrible things happen and the POV doesn't appear to fully recognize that that's the case. Occasional "Graphic depictions of violence" (see M) and Major Character Death.
(Though... does anyone look at those graphics and actually get mileage out of them? Like, if you want that info, can you look at that square and easily determine whether it's something you want to read or not? Because I definitely needed to use the alt text to even guess what the symbols were supposed to mean. I'd say "well, this isn't good design" but I don't tend to read headers or tags in the first place (just summary and cut-text, if applicable), so I shouldn't be the one to make that determination. XD