The Hanna-Barbera Saturday morning cartoon character, Space Ghost, is reported to have been created by comic book veteran, Alex Toth. Toth worked for H-B as a "designer and idea man." See the story on Space Ghost at Don Markstein's Toonopedia.
I'm aware that Space Ghost had a finish to his animated career as a talk show host on Cartoon Network. I never saw him there, preferring to remember him as he was on his first go-round. This Gold Key one-shot was published in 1966. Dan Spiegle did the artwork.