We start the list (or finish it, if you’re reading 1 to 100) with a longtime staple of public domain movie sellers. Gulliver’s Travels, produced by Fleischer Studios, was just the second full-length animated film and was clearly inspired by the first, Snow White and the Seven Dwarfs.
The animation, music, and all the technical aspects are competent enough, but there aren’t any characters to root for. Gabby is too annoying to be sympathetic, and Gulliver is too wooden to be interesting. In short, this sneaks onto the IA Top 100 for its Technicolor dazzle (especially for 1939!) but there are easily 99 movies in the Internet Archive that are better.