1. George Foster's 1977: .320/52 HRs/149 RBI. The only guy to go 50+ HRs between Willie Mays and Cecil Fielder.
1a. Mariano Rivera: He has piled up 141.0 post-season innings in his career. That's close to a season and a half of work for a reliever. His post-season numbers are mind-numbing: 96 Games, 527 TBF, 0.70 ERA.
And that's been solely against either the AL wildcard or another AL division champ.