You can wacht most things on this internet archive site (just click the video link at the top to see the selection)
However you can start with these
I always forget about Archive.org, I've gotten a ton of videos and albums off there over the years - and the cool thing is it's legal and legit.
Appreciate the link for the cartoons you provided Hazelnut, I found several classic Superman cartoons in MP4 which I hope are compatible with my Sony PS3.
What a shame, crap quality ones I downloaded. Oh well.