Debian 10, which was just released today, is code-named Buster. Debian 9 is Stretch, Debian 8 is Jessie, and the earlier ones Wheezy, Squeeze, Lenny... which are all Pixar's Toy Story characters!
It turns out, at the time Debian made its first release with a code name, Debian 1.1 Buzz (yes, Buzz Lightyear), the project leader at the time (Bruce Perens) was working at Pixar.
You may find the other Debian code names in A Brief History of Debian.
If you look closer to the Debian 10 wallpaper, which is the cover image of this post, you will notice there is a hidden shape of Buster, Andy's pet dog.