I've got 8,554 Cubs cards from 49 different brands listed on a spreadsheet. A random number generator picked five cards, one each from the past several decades.
1950s / 1960s: Topps 1959 #113 Taylor Phillips This guy was well before my time, so I knew nothing about him. So I looked him up on baseball reference. They used this card for the picture of him. Phillips played for four teams over a six seasons, with the Cubs being his second stop. He was not very good for the 1959 Cubs. He made 7 appearances, mostly in relief and was 0-2 with a 7.56 ERA. On May 12 the Cubs traded him to the Phillies.
1970s:Topps 1973 #21 Randy Hundley This picture was taken at Shea in 1972. After an injury plagued three year span, 1973 was Randy's last season as a full time regular with the Cubs or with anyone else. He played in 124 games but hit only .226. It would be safe to say that by 1973, he had broken down. After the season, he was traded to the Twins.
1980s: Upper Deck 1989 #107 Shawon Dunston Here is Dunston's card from Upper Deck's first set. Dunston had an OK year in 1989, as the Cubs came out of nowhere to win the NL East. He hit .278 (a career high up to that point) with 9 homers and 60 RBIs. He started out the season slowly, hitting only .215 through his first 50 games and then got hot and hit .329 in his next 50.
1990s: Fleer 1998 #239 Lance Johnson The One-Dog. This is a great looking card. Known more as a member of the other Chicago team, Lance came to the Cubs towards the end of the 1997 season. A hand injury kept him on the DL for most of the first half of the season. He was activated on July 14 and hit .313 for the rest of the year.
2000s: O-Pee-Chee 2009 #555 Moments July 31, 2008 You would think that something special would have happened to the Cubs on this date, but it didn't (though the Cubs did spank the Brewers that day 11-4). This card talks about how the Cubs ended the month of July with the top record in the National League. But on July 31 the Cubs were five games better than the next team in the NL. That isn't a "moment" in my book, but hey, what do I know??