I might end up feeling like the guy trying to start the wave in the Geico commercial, but I went ahead and wrote out mine...
So here is everything I have in progress. This may take a while. In semi-chronological order by sport, sort of....
1960 Topps baseball
After finishing 1959 Topps in late 2015, I started in earnest on 1960. My main man Marv has hooked me up with most of the latter part of the set, and now I'm down to the big guns. McCovey RC, Mantle, and Snider are my last three. Might be down to the Mick shortly.
1970 and 1972 Topps baseball
I've been striving to finish these two for a couple years. The last few just seem to elude me. And I'm not even trying to build minty fresh examples of either set. They started with VG-ish bulk lots, so I can go with cheaper high numbers when I find them. But they've lingered on the want list thru a couple Nationals now. I gotta get 'em killed off this year.
1964 Topps baseball
'64 is going to be the primary vintage build after '60, '70 and '72 are all done. I've started it officially this past summer, but there's still plenty to go. Haven't cut down many of the stars yet. And the majority of what I have so far is above #400.
These started out as a lot I bought from a neighbor of a good friend. Haven't paid nearly as much for the rest of the singles I've obtained since then. These are cheaper than I thought! Even in Just-Over-Mediocre condition like I've been getting. Only have one or two big stars so far though.
Been picking these up at shows for about a year or so. Always liked them, but hadn't started shopping really hard for them until recently, so I always thought they were cool but unaffordable. Starting to cure that impression.
Craploads of other set builds
There are whole pages dedicated to my set wants for baseball, football, and hockey, plus one for golf, basketball, and non-sports. I'm always trading and scouring dealer boxes for hits to anything on my lists. Some entries I'll break out in detail here.
T205 New York Giants Team Set
The picture at the top of my wants page for this collection is the inspiration for it. Until a few years ago, I never thought I would own the real cards from the early 1900's, but now I'm down to seven. I just joined the Net54 forum and discovered a lot more collectors who deal in this time period than I was aware of. Hopefully they can help me knock these out and upgrade the few that aren't graded. This is the only instance where I actually want graded cards.
I have 50+ baseball player collections that started back when I began collecting and had a couple cards of the same guy. I thought "He's cool, I like him" and started collecting everything. That multiplied over the years (and actually reduced a time or two as well). Now there are several guys I like to collect a lot and some that are just there. But at just about every show and dealer I visit, I find some oddball something that goes in one or more of these collections.
The main ones are guys that I have some connection or attachment to, whether it be fantasy football championships, watching them play in my home town and then their big-league debut, players who are favorites or relatives of friends of mine, or just guys that have some cool cards. Most of them aren't HOF'ers, but are more the fan favorite types who hit a couple All-Star games here and there. The modern guys are tougher in that they have 10x more cards issued than the vintage guys. They get binders for two at a time vs. the dozen plus that fit in there of vintage dudes.
Moon & Space
I've always been fascinated with the space program, especially the first few years when we landed on the moon. Managed to pick up a couple sets of astronauts and space themed cards here and there. A few are Heritage inserts, etc. and a couple complete sets. Nice little non-sport project.
if I didn't have a good reference to go by, my Redskins team collection would be a lot harder to manage. I found someone on eBay who had compiled team checklists before there was TeamSets4U or the Trading Card Database. I bought the book, which was hundreds of pages of two-column, micro-sized font listings of every Redskins card issued. There were a few updates, and then it stopped in 2008. I then turned to the old fashioned Word doc Have List at that point. Luckily there aren't as many football products as there once were, so it's reasonably manageable.
I just made a "quick list" to make hunting them much easier. It's one thing to have the reference, but to have to flip back and forth through 100 pages to check every card in a mixed box is a big pain and discourages me from filling in the holes. Now I can.
I've done well to find a lot of the early 'Skins for low prices, so aside from some Sammy Baughs, I'm pretty close to most of the old stuff. I keep all of the old ones in a binder, then after the late 80's, they go in the old school storage lockers, which make it easy to separate by company and year. The whole top shelf of the black wire rack is the Redskins lockers.
Errors & Variations
As part of several set builds, I love finding the variations too. Everything from '81 Donruss to Pro Set football and hockey, back to 1959 Topps and some through the 60's, and on down to the occasional modern goofs like the "non-auto" 2007 Bowman Heritage. I don't get all the legend variations from Topps flagship or anything like that, but I have spent many hours squinting at the fine lines between the stats on the back of Pro Set cards and junk wax. I actually found the Whiten above for a dime.
And the list goes on...