Pre 1960s: Bowman 1954 #173 Dee Fondy I may have to upgrade this card some day...there's a bit of the left side border missing. Fondy was the Cubs starting first baseman from 1952 - 1956. The 1954 season was a bit of a letdown; his average fell by 24 points and his homer (from 18 to 9) and RBIs (78 to 49) dropped too.
1970s: Topps 1970 #456 Don Kessinger All Star This card has a nice posed shot of Kess at Shea Stadium in 1970. In 1969 Kessinger made the All Star team for the second year in a row. In fact, the entire Cubs infield (Santo-Kessinger-Beckert-Banks-Hundley) made the team.
1980s: Fleer 1981 #309 Doug Capilla This is from Fleer's first modern set. Capilla pitched in 42 games for the 1981 Cubs, all out of the bullpen. He was 1-0 with an ERA of 3.18 He was traded after the season to the Giants, but the Giants released him at the end of spring training and he never pitched in the major leagues again.
2000s: Bowman Chrome 2011 #207 Darwin Barney Refractor Another first: a card from the Darwin Barney player collection. In fact, I put together an entire rainbow of these last year. You'll just have to take my word for it that this is a refractor; it's hard to tell with the scan.