Mirror

Mirror: A bizarre hybrid parallel/insert that Topps unleashed upon The Hobby in the late 2000s, presumably after someone in the office said, “What if we made collecting baseball cards feel like assembling a 1200‑piece jigsaw puzzle where every piece is the same shade of beige?”

The flagship example was the Home Run History marathon from 2005–08 Topps Baseball, where Topps "honored" Mickey Mantle and Barry Bonds by printing one card for every home run they hit. That meant 536 Mantles and 762 Bonds cards — each one looking so identical you’d swear Topps was running a psychological experiment to test collector patience.

And because Topps never met a bad idea it couldn’t beat into the ground, they followed up with 2007 Topps Moments & Milestones, a set composed entirely of mirrors. It was like déjà vu, but weaponized.

Eventually, Topps seemed to realize that collectors might not want to sort through a small nation’s worth of indistinguishable cards, and quietly buried the mirror concept after 2008. A mercy killing, really.