Greatest Southpaws of All Time - Pre 2015 (No Order): Marvin Hagler Pernell Whitaker Manny Pacquiao Tiger Flowers Vicente Saldivar Flash Elorde Young Corbett III Sergio Martinez Jose Luis Ramirez Hector Camacho Joe Calzaghe Daniel Zaragoza Freddie Miller George Chaney Lew Tendler Marc Johnson Pongsaklek Wonjongkam Ronald "Winky" Wright Antonio Tarver Paulie Ayala Zab Judah Paul Williams Horacio Accavallo Ayub Kalule Chad Dawson Throw some names out there, I know I missed some, keep it 2015 (prime) and before. I will be doing a current southpaw post later.
Tiger Flowers, the Georgia Deacon, was an ATG. Defeated Harry Greb twice late in Grebs career, although both contests were very close and some thought the decisions were controversial. Greb had only 1 good eye at the time.
Whitaker, Hagler, Pac, and Saldivar are the four greatest southpaws of all time. After that it gets tricky, but I almost wanna say that Galaxy is #5.