Lisa Hix unearths a treasure trove of them, which date from the 1840s to the 1940s. Much of the time, the senders weren’t joking:
You have to remember that often they were sent anonymously. They were to say “Your behavior is unacceptable.” For example, there are quite a few cards that mock men with babies on their laps as being henpecked—the kind of thing now we would think was a man doing the right thing by taking his share of child care. But these cards were specifically designed to make the man seem emasculated and disempowered by being left holding the baby. Or there’d be images of women holding rolling pins, threatening their husbands.
The people sending such cards were usually not either one of the couple. It wasn’t the wife sending to the husband or the husband sending to the wife. It was somebody outside, looking in at their relationship and saying, “This doesn’t conform with what’s expected.” In that way, they did enforce social norms. Sometimes they seemed to be saying, “Change your behavior, or else.” There’s almost this threatening element to them.
(Image from a vintage postcard on Ebay, via Hix)