As many on here have mentioned, although King is definitely a master of horror and has more or less defined what we consider to be the current horror genre, his status as such also sort of acts as a double edged sword and gives him an “infamous” reputation with much of the general population which I believe causes a lot of people to miss out on his extensive, and quite wonderful, non-horror or not-really-horror library.

As others have mentioned, Shawshank and Green Mile are the most well known of his barely-horror works. 11/22/63 is also very good. I would highly recommend the Stand as well as I consider it more of an epic with very few horror moments (I would say it actually has zero “horror” in it, but my definition may be tighter than others), but it is quite long. The Dark Tower series is my favorite series of all time and certainly isn’t horror either, but it does have a few horror elements sprinkled throughout the 7 (technically 8) books, although they’re pretty few and far between.

Also, Hearts in Atlantis is a must read.

Honorable mentions for Duma Key, Firestarter, Dolores Claiborne, The Girl Who Loved Tom Gordon and Eyes of the Dragon. And a bunch more I can’t think of at the moment