Google allows you to use "Search Operators" to filter results. You can use these to find repositories of Public Domain movies.
These are official, high-definition downloads from the studio. You keep them for 30 days, but once you hit play, you have 48 hours to finish. The catch? You cannot permanently keep the file (it’s DRM-protected), but you can watch offline. For 99% of users, "download for offline viewing" is the same as "downloading." how to download movies for free from google