Figshare has a subject term taxonomy called "category" to help make research data more findable. The taxonomy comes from the Australian and New Zealand Standard Research Classification (ANZSRC) for Fields of Research (FoR) first published in 2008 and currently undergoing a review (2019). Because it is Australia/New Zealand specific, there are some terms that we in the U.S. might find useful such as African-American Studies or Native American Studies that are sadly absent.
"The categories in the classification include major fields and related sub-fields of research and emerging areas of study investigated by businesses, universities, tertiary institutions, national research institutions and other organisations."
It Is Known that this taxonomy is Not Perfect for use at the Smithsonian. As such, please supplement any category term chosen with useful keywords. Keyword terms can use other controlled vocabularies (LCSH, MESH, etc.) or can be acronyms or specialized terms that only you find useful!
For a full list of the available categories:
A slightly more structured version for browsing with the terms organized by "Division" on multiple tabs can be found on OneDrive: ANZSRC_researchfields_figshcat.xlsx
a flat list of the categories (as published 2019-08-02) is attached to this page - you must download it to see it