Woodworkers are a social bunch, and there are a few popular forums where people share thoughts on tools, discuss technique at length, and—of course—upload their plans. Some of the most active online woodworking communities include Lumberjocks, Woodworking Talk, Wood Magazine, WoodNet, Kreg, and Sawmill Creek. Search those to see if they have what you’re looking for (either with their built-in search tool or with Google’s site-specific search, e.g. site:lumberjocks.com side table).
You can also use Google image search to research a project. Unlike the PDF search, the image search provides a photo of what the project will look like, which is helpful in determining if you want to pursue building it. By doing an image search for how to build a step stool, you will have a ton of options that all lead to woodworking plans of various quality. (The how to part of these is important—otherwise you’ll just get pictures of step stools.)