DOAJ is a free, full-text quality controlled directory which provides access to a variety of journals from many disciplines and in many different languages.

OpenDOAR is an authoritative directory of academic open access repositories.

Discovery service for peer-reviewed, open-access books and book publishers.

The INASP provides a directory of free and open access online resources. Coverage includes the following disciplines: agriculture, biology & life science, chemistry, earth sciences, engineering & technology, environment, humanities, information & communication technologies, mathematics & statistics, medicine & health sciences, physics, and social sciences.

OAIster is a union catalog of millions of records representing open access digital resources.

Information comes from over 1100 colleges, universities, and research institutions. OATD currently indexes 7,416,463 theses and dissertations.