9. Tom Bosley
While he might be the most esoteric of voice roles on this list, if you were watching Nickelodeon anywhere between 1988 or 1995, or if you were a parent of said audience, chances are good that you're familiar with David the Gnome.
For the uninitiated, The World of David the Gnome was an American adaptation of a Spanish children's TV series which itself was based on a Dutch children's book series called The Secret Book of Gnomes. It followed the adventures of David, wife Lisa and best friend Swift the Fox among others. For the brief 26 episode run, Tom Bosley paired the warm, fatherly charm of Happy Days' Howard Cunningham and the down-home, folksy demeanour of Sheriff Amos Tupper and infused them into the most beloved gnome this side of Travelocity.
While definitely his most notable voice role, David wasn't Bosley's only foray into the recording booth. He would also contribute the title role of Harry Boyle in the 1972-74 animated series Wait Till Your Father Gets Home, playing Mr. Winkle in The Tangerine Bear, as well as the terrifically-named B.A.H. Humbug in the 1978 Rankin/Bass special, The Stingiest Man In Town.