People collect signed baseball cards in three basic ways. Some simply collect the cards of players they admire in no particular order or grouping, others collect only players from a favorite team, while others collect entire sets.
Team collectors may collect all of the autographed cards for one team from a particular year. For example, a Mets fan might assemble the 1986 World Champions. Once all the cards are assembled, they can be matted with a yearbook or other piece of Mets memorabilia to make a spectacular display.
But the most ambitious way to collect baseball cards is to collect entire sets. Set collectors choose a particular card set, say 1987 Topps, and try to get an autographed example of every card in the set. Because some sets contain as many as 700 or 800 cards, the task can be quite a challenge.
Completing older sets, such as ones from the 1950s or '60s, is even tougher. The difficulty is not so much the big names, but obscure ballplayers who only played for a year or two. For example, Lou Ortiz, who played only a few games for the Phillies, has a 1955 Topps card. He apparently is still alive and living in the United States, but so far collectors have been unable to locate him. While Ortiz was playing, few people asked him to sign a baseball card. As a result, his autographed card is very rare, and sells for $100 or more.