The Directory of Open Access Journals was launched in 2003 at Lund University, Sweden, with 300 open access journals and today contains ca. 9000 open access journals covering all areas of science, technology, medicine, social science and humanities.
OAIster is a union catalog of millions of records representing open access resources. It was built by harvesting from open access collections worldwide. Today, OAIster includes more than 25 million records representing digital resources from more than 1,100 contributors. The records for these items are included in OCLC's Worldcat, but if you want to search just for open access content, you can do that through a separate OISter interface.
ROAD, the Directory of Open Access scholarly Resources, is a service offered by the ISSN International Centre with the support of the Communication and Information Sector of UNESCO. Launched as a beta version on 16th December 2013, ROAD has been developed during 2014.