The BHL is the world’s largest open access digital library for biodiversity literature and archives.

The directory is open to all publishers who publish academic, peer reviewed books under Open Access licenses. These publications are Open Access and meet academic standards for scholarly materials.

A large collection of open access books covering many genres and disciplines.

The National Science Digital Library provides high quality online educational resources for teaching and learning, with current emphasis on the STEM disciplines.

A large database of open access books and other materials.

OTL is an initiative by the University of Minnesota intended to help faculty members quickly find and assess open textbooks in use at other institutions of higher education The library has collected dozens of open textbooks that are currently in use at higher educational institutions or affiliated with a higher education institution, scholarly society, or professional organization