Cindy - Lou Who is also popular. She is seen as a symbol of innocence in the Whoville world, and fan fictions may show her growing up and facing new challenges while still maintaining her kind heart.
One interesting concept could be exploring the backstories of the Whos in more detail. For example, how they built their unique houses or what their family traditions are.
The Grinch is a fictional character. He is a green, furry creature who lives on a mountain above the town of Whoville. He hates Christmas and decides to steal all the Christmas - related things from the Whos in Whoville.
The Grinch is purely fictional. He's become a beloved character in children's literature and media, but he doesn't exist in reality. His antics and personality are all part of the fictional world.
The Grinch is purely fictional. It was made up to bring joy and tell a heartwarming tale during the holiday season. There's no basis in real events or people.