All MAST catalog holdings are available via a ConeSearch endpoint.
A high-level science product was produced cataloging star clusters within the HLA:
compact star cluster catalogs are presented for 20 nearby, star-forming galaxies using observations from the Advanced Catalog for Surveys (ACS) and source lists generated by the Hubble Legacy Archive. Results based on these cluster catalogs are published in the paper "The Luminosity Function of Star Clusters in 20 Star-Forming Galaxies Based on Hubble Legacy Archive Photometry" Whitmore, AJ 147:78. A typical cluster luminosity function can be approximated by a power-law, with an average value for the index of -2.37 and rms scatter = 0.18. The uniform database provided by these HLA catalogs results in a small scatter (0.5 magnitude) in the correlation between the magnitude of the brightest cluster (M_brightest) and Log of the number of clusters brighter than M_I = -9 (Log N).
More information on the catalog is available at https://archive.stsci.edu/prepds/hlastarclusters/.
All available missions are listed at http://archive.stsci.edu/vo/mast_services.html.