G.I. Joe: A Real American Hero – Hasbro (1982–1994)

Hasbro’s 3.75-inch O-ring era redefined action figures with military-themed heroes vs Cobra villains, deep character bios, and a massive ecosystem of vehicles and playsets. Early 1982 straight-arm figures gave way to swivel-arm battle grip (’83) and improved articulation through the mid-80s, while file cards (penned from the lore by Larry Hama) and blueprint sheets turned every release into world-building.