* The Cat in the Hat: The Cat, Thing 1, Thing 2, Sally, and the unnamed narrator are all major characters.
* Green Eggs and Ham: Sam-I-Am and the unnamed character are the main characters, but they also interact with a variety of animals (and even a Fox) throughout the story.
* Horton Hears a Who!: Horton, the Whos, the Kangaroo, the Wickersham brothers, and many other characters are involved in this story.
* How the Grinch Stole Christmas!: The Grinch, Cindy Lou Who, the Whos, and the narrator are all key players.
* The Lorax: The Lorax, the Once-ler, the Brown Bar-ba-loot, the Swomee-Swans, and the narrator all have important roles.
Dr. Seuss's stories are usually filled with unique and memorable characters, often creating a whole cast of personalities to drive the narrative.