The BBC has a surprisingly positive and in-depth article about the controversial Fritz the Cat movie from 1972. It shouldn’t be called Robert Crumb’s Fritz the Cat, because Crumb didn’t license the production himself, and he didn’t want his name associated with it.
Fritz the Cat is available on a recent Blu-ray release. Bonus commentary is with my old pal, G. Michael Dobbs, author of Made of Pen & Ink: Fleischer Studios, The New York Years, and Mike’s cohort in film and animation history, artist Steve Bissette.
https://www.amazon.com/Fritz-Cat-Skip-Hinnant/dp/B09BF59MQR/
You can watch it here for free, sans the commentary.