Start with these popular sources to look for data or statistics on a variety of topics. Many will report statistics in tables or charts that can be copied and used in a paper and include data in formats that can be downloaded for analysis. See the companion find data guide, if you need access to other datasets or need datasets for practice. The Databases A-Z: Data & Polls list has an even longer list of data sources.
The search engines, indexes, and archives listed below search across a wide-range of data sources. The searches are open-access, but note that some of them may link to some items that are behind a paywall.
The library has compiled numerous guides on looking for data, and many are linked to on the Statistics by Topic or Type page. Below is a selection of guides which focus on using specialized data techniques.