Villains created by Hanna-Barbera Productions, an American animation studio founded by William Hanna and Joseph Barbera in 1957. Mostly those who appear in the classic cartoons like Scooby-Doo, Tom & Jerry, Wacky Races, Yogi Bear, Space Ghost, The Flintstones, The Jetsons, etc.

It's worth noting that Hanna Barbera went defunct in 2001 after William Hanna passed away on March 22nd, 2001. However, given that all their properties were absorbed by Warner Bros., which continues to produce films and shows based on them, those villains who appear in the newer movies and shows can still qualify.

This category also includes crossovers between Hanna-Barbera's series, such as Yogi's Gang, Laff-A-Lympics, or SCOOB!.