First, in "serious" literature worlds, how do you even know you are in one? In Sherlock-1 the Great Detective has been dead for 19 years, so even if you happen to be in London you would think you were in an echo or a close parallel.
Maybe more interesting is the realm of children's classic literature:
https://en.wikipedia.org/wiki/List_o..._classic_books where more fantastic things can happen...for myself, I would love to visit the world of
Wind in the Willows, which I currently am harboring a fascination for. It would be wonderful to see what Ohio is like, if England is as depicted. This might make a good Aesop-2 for someone who wants a different furry background. But what "sequels" apply...the Cosgrove Hall series or William Horwood's? And there must be half a dozen elaborated versions of Oz.