Most of the original eight divisions have their own recognized classic period. 70's for the HW's, late 70's-early 80's for the LHW's, etc. The featherweight division seems to be something of an anomaly in this regard as there doesn't really seem to be one era of featherweights people recognize as especially deep. I think that the late 60's, with Saldivar, Winstone, Legra, Famechon, and Rojas is a good choice. Other potential nominations might be the 40's, as that included the two greatest featherweights of all time in Pep and Saddler, but after that the talent pool drops off somewhat. The late 90's/early 2000's with Hamed, Barrera, Morales, Marquez, and Pacquaio might warrant a mention, but you have to conflate some a few years to make it work.
1910s. Abe Attell Johnny Dundee Johnny Kilbane Jim Driscoll Owen Moran Harlem Tommy Murphy Philadelphia Pal Moore George KO Chaney
Jofre Saldivar Olivares Chacon Legra Marcel Tury the Fury Little Red Arguello Pedroza Sanchez Ford Hafey McGuigan Azumah Gomez 1970-1985 and many names I forgot.