Frankenstein by Mary Shelly
Dracula by Bram Stoker
The Strange Case of Dr. Jekyll and Mr. Hyde by Robert Louis Stevenson
Orlando by Virginia Woolf
Anthem by Ayn Rand
A Clockwork Orange by Anthony Burgess
Cosmicomics by Italo Calvino
A Connecticut Yankee in King Arthur's Court by Mark Twain
The Metamorphosis by Franz Kafka
Against the Day by Thomas Pynchon
Haroun and the Sea of Stories by Salman Rushdie
The Collected Stories of Edgar Allan Poe
and three shelves of Stephen King's works.
To say nothing of books you might well quibble about on various grounds, such as Gulliver's Travels, The Inferno, Alice In Wonderland, and Chuck Palahniuk's Fight Club.
The thing is that while all these books are undeniably genre, it does not surprise anybody to see them shelved in Fiction & Literature. Because they're all three: Fiction, Literature, and either Science Fiction or Fantasy, depending.
Which led me to muse upon Vonnegut's famous apostasy, when he denied writing science fiction in order to be accepted by what we rather quaintly like to refer to as "the mainstream." He left a lot of hurt feelings in his wake. But his work was always headed for a place on the Literature & Fiction shelves, the same way that Philip K. Dick's and H.P. Lovecraft's works are headed there today. I think he just wanted to see it happen while he was still alive.
Above: Half a face from a children's ride in the Ekaterinburg city zoo. Not terribly relevant to the conversation, admittedly. But I'm feeling whimsical today.