Here's a set that shows up once in awhile, but no one seems to know much about. The Zipcards sets from 1954-55 have long been debated whether they are actually from that era or printed later. I know I've had my set 35+ years. They come in two sizes (smaller 2" x 2 1/2" and larger 2 3/4" x 3 1/2") and are crude photos, especially the smaller ones. Even old time Orioles collectors from the Baltimore area don't have much information about manufacturer, distribution or reason for different sizes. The sets appear to be complete at 12 cards in 1954 and 13 cards in 1955, even though after the first 10 cards in each set, the cards are skip numbered. I've never seen any other cards offered beyond the 25 pictured. Over the years, I seen a wide range of prices on sets and individual cards. I remember a set in auction years ago that went for around $5000. I don't think the set comes close to approaching that figure today, but an interesting mystery that someone might be able to solve.
1954 Zipcards
1954 Zipcards #1.JPG
1954 Zipcards #2.jpg
1955 Zipcards
1955 Zipcards #1.jpg
1955 Zipcards #2.jpg