A good source of reference material is "Sing Us One Of The Old Songs" by Michael Kilgarriff, which is a comprehensive, cross-referenced catalogue of Music Hall songs, singers and writers, starting with a core song list of the more well known and popuar compared with the more obscure songs.

If it is still in print, it is probably a bit pricey £35 back in 1999, so unless you are making a serious academic study I suggest borrowing a copy from your library first.