...What?
D&D generic? What color is the sky on your world?
Because on my planet, "D&D fiction" is its own sub-genre, instantly recognizable as standing out from any other kind of fantasy.
Other than people who are deliberately trying to mimic D&D in their writing, I'm not aware of *any* fantasy works that use Vancian casting, to name just one thing. (Even Jack Vance's works aren't all that close to what we call 'Vancian'.)
There are a thousand other things like this. The D&D druid resembles almost nothing in legend, myth, or history. The weird D&D mishmash of polytheistic pantheons with Templar clerics is utterly unique (and honestly a little silly). The D&D ranger is like nothing in non-D&D fantasy fiction. (No, Aragorn almost certainly wouldn't be a D&D ranger. He doesn't use spells, or a bow, or two-weapon fighting.) I could go on and on.
There's nothing wrong with all this. D&D has developed its own distinctive flavor of fantasy, and that's fine. I do think some bits are a little silly, as I mentioned, but hey, nobody's perfect. What D&D is emphatically NOT, is generic. It is, in fact, notoriously difficult to translate many classic fantasy tropes and characters into D&D - you end up having to pound lots of square pegs into round holes.