The Directory of Open Access Journals is a collection of over 10,000 publications, aimed at creating a comprehensive index of high quality Open Access journals. Journals which best exemplify openness and quality are awarded the DOAJ Seal.
PLOS (Public Library of Science) is a nonprofit journal publisher that publishes several Open Access science journals. Most journals are restricted to a single subject, and some have subjective selection criteria, but PLOS ONE accepts all technically and ethically sound research.
PubMed Central is an archive of freely available biomedical and life science journal articles compiled by the US National Institutes of Health’s National Library of Medicine (NIH/NLM). Over 3.5 million articles are available.