Parallel cards are essentially another version of a set or subset within a product. They usually differ from the base version through different coloured borders, foil treatment or SerialNumbering. Other parallel versions can involve autographs, or different types of memorabilia. BeAPlayer is an example of a set with an autographed parallel version. Some memorabilia sets featuring jersey swatches have a parallel version featuring a patch, as a type of premium memorabilia.

Probably the very first parallel set in the current sense were the Topps Tiffany sets of the 80s. Another example is 1991 Topps Desert Storm baseball. The Desert Storm cards had a small foil stamp with a palm tree logo on the front of each card, which was otherwise identical to the regular Topps card of that year. Only 6,300 cases were produced with the intention that they be shipped to the troops in Iraq. It was a nice jesture, but in reality most of them never got farther than Shaw A.F.B. in South Carolina. Desert Storm cards are still scarce and command a pretty penny today.

The first parallel as we know them now are the Gold cards in 1992 Topps baseball. The Topps Gold cards were identical to the regular Topps cards, except that it had a Topps Gold logo on the back and the front had the player's name and team name embossed in gold foil. At first, demand for these cards was very high because of their scarcity (792 cards in the set, with just one Gold card per 36 pack wax box). Topps also produced a "Gold Winners" parallel that year in association with a contest. The "Winners" were similar to the regular Golds but had the word WINNER stamped on them. Originally, winners of a scratch-off contest (which was inserted at the rate of one-per-pack) would receive a pack of ten "Gold" cards. But the scratch-off cards were compromised, and as retaliation, Topps stamped the word "Winner" on each card.

Leaf followed with a parallel of their own 1992's Leaf Black Gold, a very attractive black-bordered parallel to their base set that was inserted at the rate of one-per-pack. After that, parallels abounded, and still do, in the form of different foil or ink colors, design elements, die-cutting, or photo selection, though their appeal has certainly worn off in most cases. It hasn't helped that certain companies, such as Donruss-Playoff, have taken the parallel concept to lengths that border on near self-parody.

Base and Matte Parallel 2005-2006 Beehive Hockey

1999-2000 Pacific Prism and Assorted Parallels