I would bet that very few of the following get taught academically in courses on the novel. They tend not to fit in.
Gerald Hanley – Noble Descents
Alexander Kielland – Skipper Worse
Rebecca West – The Birds Fall Down
Eden Philpotts – Children of the Mist
Henry Adams – Democracy
Brian Moore – The Emperor of Ice Cream; The Statement; The Lonely Passion of Judith Hearne (the last of these is tough to read because it is such an unsparing depiction of a very bleak life)
Mario Puzo – The Fortunate Pilgrim
Sue Kaufman – Diary Of a Mad Housewife
Kathryn Hulme – The Nun’s Story
Joseph Hergesheimer – Tampico
Jose Maria Gironella – The Cypresses Believe in God (about the Spanish Civil War; with 3 sequels, the last of which hasn’t, I think, been translated into English)
Uwe Johnson – Speculations About Jakob
John Lanchester – Mr. Phillips
George Borrow – Lavengro (continued by The Romany Rye)
Lew Wallace – Ben Hur
Some famous writers have less well known works that are outstanding; somehow they get overlooked:
Dostoyevsky – The Insulted And Injured
Henry Fielding – Amelia
Henry James – The Tragic Muse
Nathaniel Hawthorne – The Marble Faun
There are also some very good unfinished works of fiction by famous writers:
Jane Austen – Sanditon
Alexander Pushkin – DUBROVSKY
Dickens – The Mystery Of Edwin Drood
Albert Camus – The First Man
In concluding, let me purloin some books from the category of popular or genre fiction. You probably wouldn’t want to call them “great,” but I’m very glad that I didn’t miss them:
Eugene Manlove Rhodes – Paso Por Aqui
Robert Cormier – The Chocolate War
Edith Pargeter – Reluctant Odyssey (What am I doing recommending this on its own, when it’s the second of a trilogy? Because I read it on its own.)
Mary Pat Kelly – Special Intentions
John Meade Falkner – The Nebuly Coat