The law library website’s databases link is the place to find the best database for your search. On that page, the A-Z lists are a comprehensive list of what is available to you.
Ask one of our reference librarians if you don't know which database to start with for your research.
If you need to do any legislative history research, or otherwise find legislative material, the ProQuest databases are excellent. Legislative history can be a little tricky the first few times you have to deal with it, so don’t hesitate to ask a librarian for help.
The Government Printing Office (GPO) is an incredibly useful website. Government laws and many other publications are available on this site.
More obscure documents created by Federal agencies may be most easily found using the advanced search features of Google. Limit the search to .gov domains and .pdf documents.