For me the (probably incomplete list) is:

Connie Willis: Doomsday Book (three times)

Neal Stephenson: Cryptonomicon, Anathem, Quicksilver, The Confusion, The System of the World (twice or three times)

Frank Herbert: Dune (three times)

Tolkien: Lord of the Rings (three times)

Stephen King: Salem's Lot, The Shining, It (three times each)

Stephen King & Peter Straub: The Talisman (twice)

Vernor Vinge: A Deepness in the Sky, A Fire Upon The Deep, Rainbow's End (each twice)

Tracy Kidder: The Soul of a New Machine (twice)

Larry McMurtry: Lonesome Dove (twice)

Ross Thomas: Chinaman's Chance (twice)

William Gibson: Neuromancer, The Peripheral, Agency (each twice)