I think most of Stephen Kings books would fall into this catagory. A lot of his books are set in our world and the magic/fantasy elements that exist are only known about by a few people. For example in the book The Shining the main character is a boy who has the ability to see things other people can't. I would suggest The Green Mile, The Shining, It, Carrie, Lisey's Story,and Duma Key. Those are a few off the top of my head that are by Stephen King and would fit your criteria.