Since Nissl brought it up, I guess I'll post "Crusader Rabbit".
"Crusader" has the distinct honor of being the first cartoon made exclusively for television. Production began in 1948-49, but it didn't debut on television until August 1, 1950, on a Los Angeles TV station. Ultimately it was syndicated to over 200 stations. It was supposed to be shown on a network, but NBC decided to syndicate it to their affiliates instead.
It was created and produced by Jay Ward and Alex Anderson through their Television Arts Productions studio in Berkeley, California. Since neither men had experience in television at the time they signed with TV executive Jerry Fairbanks to represent them. The cartoons were produced with extremely low budget. There were barely any animation, relying instead on the voice tracks and beautifully drawn stills to tell the story.
Voices were Lucille Bliss as Crusader (she would later voice Smurfette and the teacher in "Invader Zim"), Vern Louden as Rags Tiger, and Roy Whaley as the narrator.
Things got a bit ugly, however. Ward and Alexander fought suit against Fairbanks over who owns the rights to the show. As it turns out Fairbanks sold it to an executive named Shull Bonsall. He owned an animation studio called TV Spots and decided to produce new episodes of "Crusader" in color through it. Bonsall intimidated Ward and Anderson into selling their studio to him, and any and all rights to the Rabbit.
Thus the color episodes were made in 1957. All the voices stayed except Lucille Bliss, who was replaced by GeGe Pearson. Here's the sad story of what Bonsall did to Lucille Bliss's career
Alex Anderson decided he had enough of animation and went to work in advertising; he died in 2010 at the age of 90. Jay Ward, however, decided not to give up and sold a little show called "Rocky and Bullwinkle"; the rest is history.
Here are some samples1950 SERIES
Produced by Television Arts Production
195 episodes (10 storylines serialized into cliffhangers)1957 SERIES
Produced by Capitol Enterprises and TV Spots
260 episodes (13 storylines serialized into cliffhangers; it was later re-edited into 13 one-hour "movies" for TV)