Hey Arnold! (found pitch pilot of Nickelodeon animated series; 1994)
From The Lost Media Wiki
Hey Arnold! was a Nickelodeon cartoon created by Craig Bartlett that aired from 1996 to 2004. As with most shows, a pilot was created in 1994 for the creator to show to the people running the network. While it was never aired on TV, it was shown before the theatrical release of Nickelodeon's first live-action movie, Harriet the Spy. When the movie came out on VHS, however, the pilot was not included with it, and while it was "remade" into the season one episode 24 Hours to Live, the original version went unreleased to the public. However, on April 22nd, 2012, the pilot was finally uploaded to Youtube.
Update: If you're having trouble viewing the video, an alternative link to it can be found here.