Answer: They are the only catchers in MLB history to have more than one .300 AVG| .400 OBP | .500 SLG season.
that's a good trivia question. In those eras, a 300/400/500 year roughly translates into at least a 140 OPS+. So i decided to see how many seasons (w/ at least 400 PAs) each catcher had with an OPS+ of 140 or higher.
9 - Piazza
5 - Hartnett
4 - Bench, Simmons
3 - Dickey, Torre, Campanella, Bresnahan
2 - Cochrane, Lombardi, Yogi, GCarter, EHoward, Freehan, Ewing, Tettleton
1 - Fisk, JLopez, Munson, Kelly, Daulton, Hargrave
The cutoffs are somewhat arbitrary, and a few guys (Ewing, most notably) would have had more years if the cutoffs were expanded even slightly.
No commentary, other than to ponder if we shouldn't start considering Mike Piazza as the greatest catcher of all-time. Can the defensive deficiency be nearly enough to offset the batting dominance?