Here we go:
Topps Complete Sets I have a 50 year run of complete sets, from 1969 to 2018. I started with 1969 because that was the first year I collected cards.
Wax Pack Collection This coincides with my run of complete sets.
Player Collection I have a player collection for five players - Darwin Barney, Ernie Banks, Andre Dawson, Ryne Sandberg, and Billy Williams. The ones that get the most of my attention are the Barney and Williams collections.
Relics and Autographs My rule -- if a player has a relic card issued in a year he played for the Cubs and it shows him as a Cub, I have a relic. Same rule for autographs. As far as I'm aware, I've got all the players covered that meet the rule.
Allen and Ginter Complete Sets This set really caught my fancy when I returned to collecting in 2008. The first Ginter set came out just two years earlier, so I was simple to go back and get the missing sets and then add a new one each year.
First Year Complete Sets This compliments my Cubs team sets. I have first year complete sets of 58 of the 130 brands in my Cubs collection. I was much more into this seven or eight years ago, but have really cooled off.
I have a few other baseball, but not cards, collections and they are all Cubs-related:
Roster Books / Media Guides - from 1957 to 2017 (with 2018 to come in a few weeks)
Scorecards - from 1948 - 2017 (I'll pick up 2018 once the season begins)
Schedules - from 1961 - 2018