In 2008, audiences were horrified to learn that the skull used by David Tennant in the Royal Shakespeare Company's then-current production of Hamlet was the real skull of composer Andre Tchaikowsky that he had willed to the company for that specific use (and even more horrified to learn the company never stopped using it even though they claimed they had), but they were far from the first production to shop for props at the morgue.
Hamlet's use of real skulls dates back to at least 1755 and probably way before then, but they were just grabbed at random from a vault full of bones at a local church (which was apparently a thing?), so nobody knew whose they were. Argue amongst yourselves as to whether that's better.
The first identified skull that we seem to know about is also the most celebrated, belonging to a stagehand named John Reed, who worked at (and left his skull to) a Philadelphia theater in the 1800s. It was used (and signed) by just about every important Hamlet of the century before coming to rest at a library in the University of Pennsylvania. Things really got going in the 1860s, when Junius Booth (John Wilkes's dad) somewhat bafflingly received the skull of a man with whom he'd once shared a jail cell and gave it to son (a different one), who was playing the tortured Danish prince on Broadway, and the skull of English actor George Frederick Cooke was dug up for one last hurrah. A dude even paid a Buenos Aires theater to use his skull in 1955, and many more tried but failed because it turns out skull preservation and delivery is harder than you'd think, and finding actors willing to use it is even more so. It's even possible that the skull of Shakespeare himself has made an appearance because it's sure not in his coffin.
Tennant wasn't even the last Hamlet to juggle human remains. In 2009, Jude Law insisted upon using a real skull, which was "acquired from a Salt Lake City dealer, donor name left anonymous." The most important takeaway here is that Jude Law has a skull guy.
Top image: Royal Shakespeare Company/Wikimedia Commons