The Research Data Alliance Metadata Standards Directory Working Group (MSDWG) ran from August 2013 to March 2015, with the aim of building a directory to promote the discovery, access and use of metadata standards relevant for research data. The work was conducted in three stages. First, the group examined existing metadata standard discovery tools and compared them against its own list of requirements. Second, the group updated and extended the information contained in the UK Digital Curation Centre's Disciplinary Metadata Catalogue. Third, the group migrated the information in the DCC directory to a new directory hosted on GitHub. In parallel with this, the group collected case studies that will inform future development of the directory under the auspices of the Metadata Standards Catalog Working Group (MSCWG).