National Science Foundation | Ford Foundation | Rockefeller Foundation | John Simon Guggenheim Memorial Foundation | Electronic Frontier Foundation | Bill & Melinda Gates Foundation | New York Foundation for the Arts | Mozilla Foundation | Guggenheim Foundation | Alexander von Humboldt Foundation | Andrew W. Mellon Foundation | Wikimedia Foundation | Apache Software Foundation | foundation | Make-A-Wish Foundation | John D. and Catherine T. MacArthur Foundation | Clinton Foundation | Open Software Foundation | Konex Foundation | Foundation series | Cystic Fibrosis Foundation | Carnegie Foundation | Solomon R. Guggenheim Foundation | McKnight Foundation | Japan Foundation | Ingram Merrill Foundation | Helms Foundation College Basketball Player of the Year | Free Software Foundation | Calouste Gulbenkian Foundation | British Heart Foundation |
Castro is affiliated with the Open Society Foundation, the Tides Foundation, the Democracy Alliance and the Association of Community Organizations for Reform Now.