Labor racketeering, extortion, loan sharking, bookmaking, gambling, horseracing, numbers, bootlegging (alcohol, records), armed robbery, burglary and of course real estate, banking, trucking and olive oil.
Because of Vito's preferences and the disdain he had for Tattaglia I doubt the Corleones were directly involved in prostitution but as we see by the time of Michael's ascent that probably was no longer the case.
"When the snows fall and the white winds blow, the lone wolf dies but the pack survives." Winter is Coming Now this is the Law of the Jungle—as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die. As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.
