The first line of Shirley Jackson’s Haunting Of Hill House is a banger, the complete first paragraph is incredible.
No live organism can continue for long to exist sanely under conditions of absolute reality; even larks and katydids are supposed, by some, to dream. Hill House, not sane, stood by itself against its hills, holding darkness within; it had stood so for eighty years and might stand for eighty more. Within, walls continued upright, bricks met nearly, floors were firm, and doors were sensibly shut; silence lay steadily against the wood and stone of Hill House, and whatever walked there, walked alone
My usual go-to recommendations for Stephen King readers looking to branch out a bit are The Good House by Tananarive Due, Ghost Story by Peter Straub, and The Kind Folk by Ramsey Campbell.