What? In all this discussion of actual literature I dare to mention that black stain that is Fanfiction??
The reason why is this; if a person is willing to dig through all the crap that exists in the fanfiction world there are those stories that take the fandom and create another great story with it. This is for us to share those great stories . . . so we don't have to do the work of digging through all the crap.
There is some great fanfiction out there.
I know it's not literature, but I posted a fanfic plot to the next Superman movie which got featured on Spill.
I also posted the whole series here.
(The one that got posted was the second film in the saga.)
Technically, I think the League of Extraordinary Gentlemen is fanfiction, since Moore mainly tells a story using existing characters (that are not legends) which he didn't create. Thank goodness for public domain.