Today in 1994, the book "The 50 Greatest Cartoons" from animation historian and future Cartoon Brew co-founder Jerry Beck was first published. Now, anyone could list what they thought the best cartoons they've ever seen was, but Beck went one step further. He polled 1,000 people in the animation industry for their favorite animations under the criteria that it was "traditional" cel animation, from North America, and under 30 minutes in length.
Of the 50 cartoons, there are a lot of Looney tunes and Disney shorts, a good amount of Tex Avery, Fletcher Studios, and UPA animations, and even a few independent animations. It's mostly older stuff with the most contemporary short being the Canadian classic "The Cat Came Back" from 1988. And as for the award for best cartoon of all time? That honor goes to the Bugs Bunny short "What's Opera Doc", directed by Chuck Jones. I wonder how this list would be different if you made a similar survey with contemporary animation professionals today?
I'd love to see that updated list, maybe you should do that new survey yourself?