Posted By: 
GlennI'm aware that there are numerous collectors who are working on a "set" of Hall of Famers, some (though not primarily pre-war focused collectors) who are working on a "set" of 500 HR club members, some who are working on a "set" of 3,000 hit club members, and some who are working on a "set" of 300 game winners.  
I've considered putting together similar (but always more esoteric) sets, and I think I may have finally decided on one.  I'm curious to learn what other sets of this ilk people here have completed or are currently working on.  Players with lead-off extra base hits in the World Series?  Middle-relievers who won All-Star games?  Pitchers who started opposite Ruth?  The 150 triples club?  The 30-game hitting streak club?  Youngest player to start for each team?...