Nostalgia for the 1980s is at its peak. From "Stranger Things" to synth-pop playlists, the '80s vibe is everywhere — and collectibles from that decade are hotter than ever, including Happy Meal toys.

In the 1980s, McDonald’s Happy Meals became a cultural phenomenon, and the toys tucked inside quickly turned into collectibles. For kids, they were a fun surprise, but today many of those small ...