Patience however is a virtue.
I'm not sure what to make of these baseball cards, if you can call them that. They are more like a printing plate.
They come from the 1999 SkyBox Molten Metal set.
The 1999 SkyBox Molten Metal set was issued in one series and distributed in six-card packs with a suggested retail price of $4.99. The set features 100 of the game's top veterans in the Metal Smiths (cards 1-100) subset with an insertion rate of 4:1 pack; 30 of today's power hitters in the Heavy Metal subset (101-130) inserted one per pack; and 20 of 1999's hottest rookies in the Supernatural subset(131-150) with an insertion rate of 1:2 packs. The cards are silver-foil on 24-point stock and enhanced with additional holofoil and wet laminate.
These cards are from the SkyBox Molten Metal Xplosion parallel set
Randomly inserted in packs at the rate of one in two, this 150-card set isAlthough it wasn't the sample card that I was able to pick up, instead 7 'metal ' cards:
parallel to the base set printed on metal stock with added etching, rounded
corners and foil stamping. A promotional card featuring Kerry Wood was
distributed to dealers and hobby media several weeks prior to the product's
national release. This unnumbered card can be readily identified by the text
"PROMOTIONAL SAMPLE" running diagonally across the back.
#15 Ruben Rivera Padres
#24 Sean Casey Reds
#32 Ray Durham White Sox
#34 Richie Sexson Indians
#75 Eric Karros Dodgers
#145 Sammy Sosa Cubs
#146 Kerry Wood Cubs
Not sure which genre of collecting to place these. Oddball, gimmick, parallel, inserts, alongside printing plates? At first I thought that Skybox must have had a hell of a time disguising these to ward off would be pack searchers. But the weight of these cards is not dissimilar to some of the blanks inserted in more recent Upper Deck products, roughly 3-4 regular cards.