USF law school faculty, students, and staff can use Westlaw to find Supreme Court briefs, petitions, and joint appendices. There is a source that combines all three types of documents, plus separate sources just for briefs, petitions, and joint appendices
USF law school faculty, students and staff can use Lexis.com to find Supreme Court briefs and petitions.
USF non-law-school students, faculty, and staff can use LexisNexis Academic to find (and print, email, or download) Supreme Court briefs and petitions.
You can use key words, party names, attorney names, docket numbers, etc. as search terms.
Coverage start at about 1936 for selected briefs. Fuller coverage for briefs in "cert. granted" cases starts with the 1994-95 term. Coverage for petitions begins with the 1999-2000 term.
For selected briefs in a convenient format, check: Landmark Briefs and Arguments of the Supreme Court of the United States.
The Zeif Library has briefs and petitions on fiche from 1951 to 2016, in Fiche Cabinets 21 through 24.
For 1951-1971, the library has briefs for full opinion cases only. Starting with 1973, the library has briefs and petitions for all cases: full opinion; cert. denied; summary disposition; and per curiam.