The two main players in research paper formats are APA and MLA, which stand for American Psychological Association and Modern Language Association, respectively, and these are the main places where you want your examples to come from. They both have sites that are full of writing and research information as well as info on how to stick to their formats.
Whether you are in college or not, college libraries and their corresponding websites are top places to find research paper examples. One of their main missions is to help people write papers, since it is something that most college students do all of the time, and as a result, they are particularly helpful.
While sites of academic institutions might be a great resource, don't discount niche sites that are created for the sole purpose of research paper examples. When looking on these, you'll see heaps of great examples and guides, just make sure not to pay because there is enough free information out there for everyone.
Never underestimate the power of a skilled and knowledgeable reference or research librarian. No one knows how to put together a paper better than they do, and they are passionate about doing so.