Beall’s List of Predatory Open Access Publishers indicates open access publishers to avoid because they provide inferior services.
Creative Commons (CC) provides a suite of open licenses to enable libre open access, i.e., the licensing of selected re-use rights.
Directory of Open Access Journals (DOAJ) provides a list of quality open access journals.
Directory of Open Access Repositories (OpenDOAR) provides a list of open access institutional and disciplinary repositories worldwide.
Open Access Directory is a compendium of simple factual lists about open access (OA) to science and scholarship maintained by the OA community.
Registry of Open Access Repositories Mandatory Archiving Policies (ROARMAP) provides a list of institutional and funder mandates, with links to the repositories and the policies.
SHERPA Juliet database provides easy access to funding body policies on open access.
SHERPA RoMEO database provides easy access to publisher policies on open access.