Cometa: The comprehensive multi-label data archive, it is a collection of multi-label datasets, available at cometa.ujaen.es in different file formats and pre-partitioned following several strategies. The dozens of available datasets can be used with tools such as MULAN, MEKA, KEEL, LibSVM and the utiml, mldr and mldr.datasets R packages. A detailed description of each dataset, including attributes, labels, multi-label metrics and label relationships plots, is also provided. The user can easily sort the datasets according to several of these metrics, choosing the most appropriate to its interest.