Some archives offer films under "Creative Commons" licenses. These allow for film archive downloads , but with conditions—such as requiring attribution (crediting the archive) or prohibiting commercial use. Always check the specific license agreement on the download page.
This could refer to searching for rare, "lost," or unreleased films found in specialized niche forums or database trackers.
For those interested in European heritage, Europeana aggregates content from museums and archives across the EU. Many items are available for download under Creative Commons licenses.