When writing this question:
I realized we miss the tag for Weird Fiction. While it would be a really specific tag, as it is a fairly niche genre, I guess that since it's a recognized genre it should have the same dignity as more broad ones (like horror, fantasy etc).
Yet, as far as Wikipedia definition go {Weird Fiction,New Weird}, Weird Fiction is used mostly for novels written between late 19th and early 20th centuries. Weird Fiction nowadays is called "New Weird" (sigh) to signify that it's, well, new.
So, we have those chances:
- We add both
- We add both, one as a synonym of the other
- We add only one of them
- We don't add any
I'm personally against the last option, but I'm really not sure about the others.