Cards. Usually with terrible jokes and barely-better-than-stick-figure drawings, probably making some artist a fortune once Hallmark has their cut, so someone does a half-laugh before throwing it out.
I tend to buy a handful of cards at a time, and I like those produced by The Royal Academy or V&A of paintings or Japanese woodblock prints. The Japanese artists would likely be fine with this given how their work was always endlessly reproducible and printed many times, but I doubt the printing of oil paintings agonised over by Dutch masters would have been the outcome they wanted.