Very rare in DVC resorts (perhaps because housekeeping comes so infrequently), less rare but still unusual in regular WDW resorts (I've never had one, my parents - traveling without kids - got some). Standard in your room on the cruise ship.
BTW, standard in the private vlla we stayed in in Mexico - it isn't just a Disney thing - every day our maid left us new animals. Unfortunately, Hurricane Wanda trashed the villa, which belonged to friends of friends.