I've got 10,607 Cubs cards from 71 different brands listed on a spreadsheet. A random number generator picked five cards, one each from the past several decades.
This card is from Bowman's first full release. They put out a set in '48 but it only had 48 cards and didn't have players from each team. The '49 set had a full 240 cards. Apparently at this time Bowman hadn't learned about the airbrush; they have Walker in a Phillies uniform, though the back lists him as a Cub. He was traded to the Cubs after the 1948 season. He spent less than half of the '49 campaign with the Cubs, as he was traded to the Reds on June 15.
1970s:Topps 1975 #363 Carmen Fanzone So much with this card.....the big '70s mustache....the felt C on the helmet.....the handwritten 23 inside the C. I've got a previous post about Fanzone here. The Cubs released Fanzone after the '74 season, so he really shouldn't have had a '75 card. He spent the year with the Padres' AAA team in Hawaii. That was his final season in professional baseball.
1980s: Score 1988 #602 Les Lancaster The good news for Lancaster in 1988: a career high 44 games. The bad news: only 8 appearances after the All Star break...appendicitis and after returning, he broke his foot and was out the rest of the season.
1990s:Upper Deck 1996 #296 Rey Sanchez Sanchez had a pretty awful season in 1996. He was the starting shortstop for the first part of the season but fractured a bone in his hand and missed most of June and July. He hit only .211 and had just one homer and 12 RBIs.
2000s: Topps Opening Day 2001 #112 Sammy Sosa This card is from the days when Opening Day had a border a different color than the base. That's much better than what they do today. Sammy made history in 2001 by becoming the first player with three 60+ HR seasons. He led the majors in RBIs (160), total bases, runs scored, and intentional walks. He was second in the NL in homers (64) and eighth in batting average (.328). The average was his career high.