Hound Town (partially lost NBC animated TV show pilot; 1989)
From The Lost Media Wiki
Hound Town is a 1989 unsold animated pilot created for NBC by Prudence Fraser with the intention of catering to a prime-time audience. It was directed by Ralph Bakshi at his Bakshi Animation studio, where he worked with animators from Mighty Mouse: The New Adventures, such as Rich Moore, Andrew Stanton and Jeff Pidgeon. Bakshi claims this to be one of his least favorite works.
The pilot found its way onto YouTube in December 2014, in low quality and with the beginning cut off, but the uploader's channel was suspended in March 2015 and it is now considered lost. However, a page on Behind the Voice Actors contains a few screenshots from the episode.