HathiTrust
HathiTrust is a digital preservation repository including books, articles, manuscripts, and more. For public domain materials, limit your search to Full-text ().
Internet Archive
Internet Archive is a non-profit digital library that includes web pages, audio and video recordings, books and texts, images, and software programs.
Project Gutenberg
Project Gutenberg is a library of more than 60,000 copyright-free epub and Kindle ebooks.
Wikimedia Commons
Many of the 80 million+ media files uploaded to Wikimedia Commons are in the public domain. For public domain materials, click on the License () drop-down menu and select No restrictions ().
Flickr
Flickr is a photo management and sharing site with billions of photographs. For public domain images, click on the Any license () drop-down menu and select No known copyright restrictions ().