I've got 8,733 Cubs cards from 51 different brands listed on a spreadsheet. A random number generator picked five cards, one each from the past several decades.
1950s / 1960s: Topps 1960 #95 Frank Thomas It always nice to see the Cubs wearing their red vests! Obviously, Frank came to the Cubs from the Reds, via a trade in December 1959. He belted 21 homers for the 1960 Cubs, good for second on the team. He ended up losing playing time at third to a rookie names Santo. In 1961 his outfield time would be cut due to another rookie, Billy Williams, so Thomas was sent to the Braves in May of 1961.
1970s: Topps 1975 Mini #363 Carmen Fanzone I think this is the first time the randomizer picked a '75 mini. But since they are just smaller versions of the regular cards, you can't really tell by looking at the scan that this is a mini; you'll just have to trust me. Fanzone didn't even play for the Cubs in 1975 because the team released him in December, 1974. Instead, he spend the season with the Padres AAA team in Hawaii. He hit only .217 and that was his final season in professional ball.
1980s: Topps Giant 1980 #5 Dave Kingman Again, you're going to have to trust me that this is a giant card. This card is from Kong's final season with the Cubs. He was hurt for half the season, and had worn out his welcome in his home town. He became a free agent and went back to the Mets.
1990s: Star 1991 Silver #72 Ryne Sandberg This is one of the 121 Ryne Sandberg cards I have from Star, and I'm still missing another 54 (which have been impossible to find!). Ryno had another decent season in 1991, hitting .291 with 26 HR and 100 RBIs. He also became the first second baseman to win nine Gold Gloves as he led all MLB second baseman in fielding. In fact, he made only four errors all season.
2000s: Topps Chrome 2005 #10 Sammy Sosa This is our second card of a player who didn't play for the Cubs the year the card was issued. Sammy bailed on the team on the last day of the 2004 season. His boombox was smashed in the locker room, allegedly by Kerry Wood, though the culprit was never identified. Sosa went from one of the most popular Cubs ever to one of the most reviled. The Orioles were suckered into taking him off of the Cubs hands and Sammy hit .221 with only 14 HR and 45 RBIs. But he did get paid $17,000,000 for that.