[smapdi]

Low-print-run sets/parallels are my favorite way to collect. I've undertaken quite a few over the years and even completed some.

2020 Topps Decades' Best Chrome (200 cards so far, need 28, difficult distribution model, print run probably surprisingly low)
2020 Topps Project 2020 (400 cards, not sure about going after the whole set or just players/artist collections, but I'd love to own the whole thing someday)
2017 Topps Silver Pack 1987 Chrome Rainbow (100 cards X 4 colors #/50-175 plus base, need 2)
2016 Panini Flawless Team USA #/20 (15 cards, complete)
2014 Panini Flawless #/20 (100 cards, need 3)
2011 Topps Lineage Mini Relic (99 cards, some wicked SPs, complete)
2011 Topps Marquee Museum Gold Frame Autos (120 cards, though maybe 15-20 were not made, I'm at 93)
2010 Upper Deck Exquisite #/75 (100 cards, 1 likely not made, missing 14, probably no more than 10% of the print run actually released)
2009 Topps 206 Silks #/50 (50 cards, got half-way, gave up)
2009 Topps Turkey Red Silks #/99 (50 cards, complete)
2008 UD Timelines Timeless Teams Platinum #/25 (100 cards, missing 4)
2007 Upper Deck Goudey Game-Used set (100 cards, complete, deceptively tough with some HTF SPs, sold)
2006 Bowman Originals Prospect Set Black Border #/99 (55 cards? Complete, but it took years to find a Hunter Pence)
2006 Topps Allen & Ginter autos (burned out pretty quick on this but I did collect many of the SPs before I did. I think paying $100-150 per card is what burned me out. But it worked out.)
2005 UD Classics Fantasy Team PR 36 (18 cards, complete)
2005 UD Origins Old Judge Gold #/20 (286 cards, missing 1)
2003-04 Upper Deck Exquisite Basketball base #/225 (42 cards, complete, sold in 2005ish for way too cheap but you can't look back)
2000 UD Ultimate Victory Gold #/25 (120 cards, need about 75, these dried up a long time ago)
1997 Donruss Signature Significant Signatures (22 cards, complete)
1975 Topps PSA 8+ (660 cards, complete, #40 on current finest registry)
1971 Topps Greatest Moment PSA 6+ (55 cards, need 4, had been aiming for 7+ but the SPs are tough)
1955 Bowman (320 cards, complete)
1941 Play Ball (72 cards, missing 6 biggest names) (neither of the last 2 are hard to complete, just takes time and money and trying to be consistent on condition, never really done)
Magic The Gathering Reserved List (572 cards, complete, though no one really collects it as a set, per se)

I gave up on a few, but in the mid-00s UD had a #/25 parallel in quite a few sets and I chased after a few to one degree or other, but they just got to be boring and/or dried up. I made some progress on the 2005 Artifacts (about 40 cards) and Hall of Fame (about 15) #/25 parallel sets before I gave up. And every year I think about going after the Heritage Black Chrome set but never do.

Currently my dream project is to complete the Independence Day parallel #/76 from a Topps base set, but at 700 cards over 3 series that seems too difficult. If they ever add it to Chrome, though, I'll definitely chase it every year.