Yes, look in the literary section of a bookstore.
I’m not being facetious, at least not entirely. There is obviously no “official” definition of what is literary and what is not. Like pornography, it’s more a case of “I know it when I see it.”
However, virtually everyone in the business would agree on most authors most of the time. Pick up the latest New York Times Book Review and you’ll see separate columns for Crime and Science Fiction, even though occasional books get individual reviews. Most of the fiction reviewed there is literary fiction, except when they review a bestseller.
And yes, absolutely without qualification, bestseller is a genre. Check Amazon for titles like How to Write a Bestseller in Forty Days or Less: An Agent’s Guide to Writing a Novel, by Barbara S. Debolt or How to Write a Best Seller: Secrets, Techniques and Success Formulas of Best-Selling Authors, by Horst A. Mehler.
All publishing today is about marketing. All marketing is about categorizing. Categorizing is as much about prestige as sales, because prestige can sell since genre usually gets ignored at a national level. Authors from Kurt Vonnegut to Lewis Shiner to Jonathan Letham yelled and whined and screamed until they were taken out of the science fiction genre to be literary. Dean Koontz went from sf to bestseller. Margaret Atwood and Doris Lessing hurled imprecations at anyone who said that their science fiction novels were science fiction instead of literary. Note that nobody ever goes the other way, although Ursula LeGuin, who for a while flirted with mainstream status, has re-embraced her acceptance of the field. Why? Science fiction writers don’t get reviewed in the major newspapers, don’t get invited onto tv shows, don’t get invited to literary events and conferences and the speaking circuit. And science fiction writers mostly get shelved together, have a limited, if assured, number of buyers, and have a short shelf life with little to no backlist. Even general fiction does better than science fiction in these areas.
So to return to your question: who makes these decisions? Everybody. Everybody but the author, with a couple of tiny exceptions.
And where is there a list? Everywhere books are sold. These categories take in thousands of names, with new ones coming in every single day. Look at the packaging, lost at the shelf location, look at the reviews. That’s the only way to tell.