This fascinating little set doesn't quite fit the definition of 'cards,' but is nevertheless widely collected within the hobby as it was produced by Topps and distributed with their other products.
These really were records, playable on a kid's turntable at home. They were distributed in traditional record sleeves (with the hole in the center to show the label) in a display box, at 15 cents each with no gum.
The record fronts feature a color photo of the artist which bleeds out onto the recorded section, with a small inset box that shows the record company name, plus the name of the song and the artist.
The backs were much more elaborately designed, and in the style of the time (this being 1968, after all). The name of the artist was at the top, followed by the title of the song, its album appearance, and other information. A biography of the group took up a large section in the middle, followed below by directions on how to play the record, and a list of records in the set at the bottom.
Curiously, all of the artists in this series (which included Stevie Wonder and Marvin Gaye) might more correctly be called R&B rather than Rock; still, it is a good collection of contemporary artists.
Note that these are difficult to find, not only because probably only a small number survived the ravages of kids' record collections, but also because they are sought by record collectors as well as card collectors.