I'm sure you know that Walt had many other creations, before Mickey Mouse but without a doubt, his short film series the Alice Comedies were groundbreaking in the 1920s, and were able to help him build up his studio after a previous bankruptcy. Using a live girl, and animation, Walt made 56 of these short films. Over the course of the series, Alice was played by four different little girls.
If you look hard enough, you'll find them on VHS, and DVD, but also, since the videos are now public domain, you will run across them on Youtube! I've included one below from Youtube for you to get a taste of.
Remember... these older cartoons sometimes portrayed things that today's cartoons might not, and could be considered not politically correct, or even violent. Please use your best judgment before watching, or allowing your children to watch.