The Library of Congress' Network Development and MARC Standards Office, with interested experts, has developed the Metadata Authority Description Schema (MADS), an XML schema for an authority element set that may be used to provide metadata about agents (people, organizations), events, and terms (topics, geographics, genres, etc.).
MADS points to the Source Codes for Subjects (link below the title here). Some of the codes are:
"Asian American Studies Library subject headings" in A Guide for establishing Asian American core collections. (Berkeley, CA: Asian American Studies Library, University of California, Berkeley)
AAT: Art & architecture thesaurus (New York, NY: Oxford University Press)
Autoridades de la Biblioteca Nacional de España (Madrid: Biblioteca Nacional de España)
AGRIFOREST-sanasto (Helsinki: Helsingin Yliopisto)
AGROVOC multilingual agricultural thesaurus. (Rome: APIMONDIA)