I can tell you about some popular fictional universes that many people find intriguing.
Middle-earth (from J.R.R. Tolkien's "The Lord of the Rings"): Middle-earth is a richly detailed and expansive fantasy world filled with diverse races, epic quests, and deep mythology.
Hogwarts (from J.K. Rowling's "Harry Potter" series): Hogwarts School of Witchcraft and Wizardry is a magical place where students learn spells, potions, and participate in thrilling adventures alongside Harry Potter and his friends.
The Star Wars galaxy: The Star Wars universe is a space opera filled with iconic characters, epic battles between the forces of good and evil, and a mystical energy called "the Force."
The Marvel Cinematic Universe: The Marvel Universe is a superhero-filled world with a vast array of characters, each with their unique abilities and thrilling storylines.
The Discworld (from Terry Pratchett's Discworld series): Discworld is a flat, disc-shaped world supported by four elephants standing on the back of a giant turtle. It is a humorous and satirical fantasy realm filled with wit and imagination.
Remember, each fictional universe has its own unique characteristics and appeals to different people based on their interests. It's all about personal preference and the kind of world or genre that resonates with you.