Traditional publishers are companies that produce, distribute and market books for physical and digital sale. They are also called trade publishers and are sometimes considered the foundation of the publishing industry. Traditional publishers include many of the “Big Five” publishing houses—Penguin Random House, Hachette Livre (Hachette Book Group), HarperCollins, Macmillan Publishers, and Simon & Schuster—as well as smaller and medium-size publishers.
Some other traditional publishers include:
• Alfred A. Knopf
• Graywolf Press
• Houghton Mifflin Harcourt
• W. W. Norton & Company
• Scholastic Corporation
• Tor/Forge
• St. Martin’s Press
• Prometheus Books
• The Permanent Press
• BOA Editions
• Coffee House Press
• The University of Arkansas Press
• University of Nebraska Press
• Wayne State University Press
• McFarland & Company
• John Wiley & Sons
If you’re interested in learning more about traditional publishing, this article from Writer’s Digest has more information: https://www.writersdigest.com/online-editor/what-is-traditional-publishing