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Babe Ruth's likeness
Old-Timers: Babe Ruth (1914-1935)
Babe Ruth is the power hitter from whom all other power hitters are descended. He led the league in homers 12 times, topping out at 60 in 1927, and retired with 714 career homers. Many years later, he's still the all-time leader in slugging, OPS and OPS+. Oh, and he could also pitch a bit, because he was a showoff like that.
Post-Integration: Willie Mays (1951-1973)
The greatest center fielder of all time and baseball's greatest living player, Willie Mays retired with a career line of .302/.384/.557, with 523 doubles and 660 home runs. He led the league in OPS five times and in stolen bases four times, and he's also arguably the best defender ever to roam center field.
Next Wave: Rickey Henderson (1979-2003)
Rickey Henderson stands alone as baseball's all-time greatest leadoff man. He stole a record 1,406 bases, and his 130 steals in 1982 still stand as a modern baseball record. He also hit 297 home runs and retired with a career OBP of .401. He's also the GOAT at speaking in the third person.
Modern: Barry Bonds (1986-2007)
Yeah, yeah. Needles and stuff. All the same, there's a limit to how much chemicals can help one pile up 762 career home runs and a career 1.051 OPS. Barry Bonds is also the only player in history to hit 500 homers and steal 500 bases. There were chemicals at work, sure, but also talent. Lots of it.