These cards were included in a variety of soundtrack products.

The earliest releases of FOTR-OST had one of these cards in each package. I don't know what the backs looked like (the black backs below are from the LOTR Trilogy set). The cards included in the TTT & ROTK were printed on cardstock weight paper. I don't know but would presume FOTR's were, as well.

The LOTR Motion Picture Trilogy Soundtrack 3-disc set contained all of the FOTR cards. These had black backs with a white icon/motif and the character's name (hand lettered by Daniel Reeve). This set also contained 13 ROTK cards. The cards were printed on glossy paper of thickness in between magazine paper and poster paper.