Brahms' ouvre numbers 122 works - starting with his piano sonata i C-major, published in 1853 and ending with his 11 choral preludes, published posthumously in 1902. In addition to his opus list are a number of other works and arrangements that Brahms did not consider part of the list, the so called "Werke ohne Opus" - marked "WoO".
For extensive details, please consult: Margit L. McCorkle, Brahms Werkverzeichnis, München, Henle HN2203, 1984