He-Man And The Masters Of The Universe Figures
Identical bodies, different heads, enormous success.
Mattel's line of chunky figures, sold alongside a cartoon that existed mainly to advertise them.
The bodies were reused across the range, which meant any figure could be any character if you lost the accessory, and everyone lost the accessory.
Castle Grayskull was the big-ticket item and about four children in every school actually had it.
Cost back then
£3.99 a figure
Goes for now
£15–£300 depending on character and boxing