This Federal produced database is a one-stop shop for general government information. USA.gov has one search box, semi-permanent subject topics, and features web pages on news topics. It is meant to be the “official” meta-site search engine of the entire U.S. government.
Govt. Info, https://www.gpo.gov/fdsys/
GovtInfo provides free online access to official publications from all three branches of the Federal Government. Through GovInfo, you are able to:
Search for documents and publications — FDsys provides advanced search capabilities and the ability to refine and narrow your search for quick access to the information you need.
Browse for documents and publications — FDsys offers browsing by collection, Congressional committee, date, and Government author.
Access metadata about documents and publications — FDsys provides information about Government publications in standard XML formats.
Download documents and publications in multiple renditions or file formats — With FDsys, users can download a single file or download content and metadata packaged together in a compressed file.
Congress.gov : https://www.congress.gov/
Congress.gov is the official website for U.S. federal legislative information. The site provides access to accurate, timely, and complete legislative information for Members of Congress, legislative agencies, and the public. It is presented by the Library of Congress (LOC) using data from the Office of the Clerk of the U.S. House of Representatives, the Office of the Secretary of the Senate, the Government Publishing Office, Congressional Budget Office, and the LOC's Congressional Research Service.