Looney Tunes

Looney Tunes is an American animated comedy theatrical short film series produced by Warner Brothers.

Throughout the years, both Hanna-Barbera and Looney Tunes have made several references to one another.

Blast-Off Buzzard

 * The Blast-Off Buzzard shorts bare similarities to the Wile E. Coyote and Road Runner shorts.

Fantastic Max

 * At the end of the episode, "Movie Star Max," there's a sequence where Max pops out to tell the viewers, "Th-th-that's it, folks!"

Flintstones

 * In the Baby Looney Tunes episode, "The Wheel Deal," the Flintmobile makes a cameo.

Hokey Wolf

 * The Hokey Wolf short, "Robot Plot," is likely inspired by the Looney Tunes short, Robot Rabbit.

Scooby-Doo

 * Scooby and Shaggy make cameos at the WB cafeteria in Looney Tunes: Back in Action, where they are voiced by Frank Welker and Casey Kasem respectively.
 * Wile E. Coyote and Road Runner make cameo appearances in the What's New, Scooby-Doo? episode, "New Mexico, Old Monster," with the Road Runner's voice being from an archival recording of Paul Julian.
 * Tweety also makes a cameo in Avery's bird watching guidebook.
 * For Warner Bros.' 100th anniversary, they teamed up with Funko to release Looney Tunes Pops with a Scooby-Doo motif.

Other

 * The concept for the unrealized project, Toing Tiger likely became the character Cool Cat.