Wiktionary
n. A small, mass-produced devotional picture
Wikipedia
In the Christian tradition, holy cards or prayer cards are small, devotional pictures mass-produced for the use of the faithful. They usually depict a religious scene or a saint in an image about the size of a playing card. The reverse typically contains a prayer, some of which promise an indulgence for its recitation. The circulation of these cards is an important part of the visual folk culture of Roman Catholics, and in modern times, prayer cards have been also become popular among Orthodox Christians and Protestant Christians, although with the latter, biblical themes are emphasized within them.
Usage examples of "holy card".
The first time I went there, it was by chance: Mass, catechism, all sorts of games, and if you won, he gave you a little holy card of Blessed Domenico Savio, that adolescent with the wrinkled canvas pants, always hanging on to Don Bosco in the statues, his eyes raised to heaven, not listening to the other boys, who are telling dirty jokes.