1. Casey Kasem as Shaggy

The radio legend and voice of the weekly American Top 40 countdown was no stranger to cartoon work and television cameos. Elsewhere in Hanna-Barbera land, Kasem was Robin the Boy Wonder on Super Friends. As a pop-culture personality, Kasem popped up in Seventies series such as Quincy, M.E. and The Hardy Boys/Nancy Drew Mysteries. Here he is playing a big part in the Charlie's Angels episode "Winning Is for Losers." Kasem passed away in 2014.

2. Nicole Jaffe as Velma

Jinkies! Canadian actor Jaffe got her big break in an Elvis flick, The Trouble with Girls, which just so happened to also feature Frank Welker, who we'll meet in a moment, and Scooby-Doo regular Vincent Price. While playing Patty in a 1969 stage production of You're a Good Man, Charlie Brown, Jaffe was spotted by Hanna-Barbera recording director Gordon Hunt, who cast her as the bespectacled Velma. She made just a few appearances in live-action series. Here she is playing the title character in the Room 222 episode "What Would We Do Without Bobbie?"

3. Frank Welker as Fred

Welker remains a legend in the business of cartoon voice-over work, with hundreds of credits to his name spanning half a century. He's been everything from Megatron in The Transformers to Doctor Claw on Inspector Gadget. Hey, Scooby, his first voice-over gig was an ad for Friskies dog food. Welker dabbled in live-action work, too. He worked with Don Knotts on both How to Frame a Figg and The Don Knotts Show. We particularly dig his turn on The Partridge Family, seen here in "My Heart Belongs to a Two Car Garage" playing Sioux. "A boy named Sioux," as Reuben jokes.

Image: Sony Pictures Television

4. Stefanianna Christopherson as Daphne

Christopherson made her screen debut on Mayberry R.F.D. in "The Harvest Ball." She's the young woman working the table at the dance. She collects tickets from Goober. A few years later, after her Scooby-Doo work, the California native appeared on both Sanford and Son and M*A*S*H. In both cases, she was credited as "Indira Danks." On M*A*S*H, she shares a memorable moment with Trapper in a shower in "Love Story," the one where everyone is trying to get Radar a date.

5. Heather North as Daphne

Christopherson voiced Daphne for the first season of Scooby only. In the second and final season, North took over the role. She had several credits to her name by that point, including a recurring role on Paradise Bay. North also guest-starred on Gidget, My Three Sons, Green Acres and The Fugitive. Here she is on The Monkees, playing Wendy, Davy's love interest in "The Prince and the Paupers."

6. Hal Smith as Various Villains

Ol' Otis Campbell, the town drunk of Mayberry, is the man behind dozens of cartoon voices. Heck, Smith was even Santa Claus to a generation of children. You know him best from The Andy Griffith Show, but he voiced characters in every single episode of Scooby-Doo, Where Are You! Perhaps our favorite is the Headless Specter, one of the more benevolent "ghosts" of the show. Spoiler alert: He's really Penrod Stillwall! 

7. Don Messick

Ruh-roh! You didn't think we were going to overlook Scooby himself? Messick was a true Hanna-Barbera titan. He was Scooby and Astro. Not to mention Boo-Boo Bear, Muttley, Papa Smurf and so much more. Oh, and Bamm-Bamm Rubble, too. That's a wide range, from dogs to babies. In 1984, he finally made the leap to live-action, landing a role on The Duck Factory, a Jim Carrey sitcom about — what else? — cartoon creators.

Image: The Everett Collection

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