UK Libraries' InfoKat Discovery is the best source for the location, SuDoc/call number, and format (paper, microfiche, electronic, online) of U.S. government publications held at UK Libraries.
Any keyword or subject search in InfoKat Discovery will pull U.S. Federal government publications into the search results if there are such publications on the topic. However, if you want to narrow your results to U.S. Federal government publications alone, use the following search strategy:
Go to Advanced Search and type in search terms into the first two boxes, and in the last box, enter the following terms: gpo mvi dgpo
These are some of the most important resources available for U.S. government publications and cover multiple types of documents as well as a variety of subjects.