Bonnie (17) by Hillygon on DeviantArt

In Toy Story 3, one of the girls at the Sunnyside Daycare is a slightly older Boo from Monsters, Inc.

Turning Red Theory Says Mei's Friend Is Secretly A Monsters Inc Character

Buzz Bradley 🌐 on X: Is that a little grown up Boo from Monsters Inc. in Bonnie's classroom in Toy Story 4? @Pixar / X

Monsters, Inc. (2001) - IMDb

Director's Commentary Track Review - Monster's Inc. - Pixar Post

All The Toy Story 4 Easter Eggs You May Have Missed

Pixar Animation Studios

Monsters, Inc. : Billy Crystal, John Goodman, Mary Gibbs, Steve Buscemi, James Coburn, Jennifer Tilly, Bob Peterson, John Ratzenberger, Frank Oz, Daniel Gerson, Steve Susskind, Bonnie Hunt, David Silverman, Lee Unkrich

Jessie (Toy Story) - Wikipedia

p16-sign.tiktokcdn-us.com/tos-useast5-p-0068-tx/e4