The Internet Archive, a 501(c)(3) non-profit, is building a digital library of Internet sites and other cultural artifacts in digital form.
Includes 30 million digital books, some require a free user account to access.
Lever Press is a scholarly press supported by more than 50 liberal arts institutions. They publish peer-reviewed, born digital, open access monographs at no cost to our authors or their academic institutions.
The University of Alberta Press makes significant titles Open Access rather than letting them go out of print, keeping them available to researchers and the general public. Look for a "Download OA File" link below a book's title.