I am surprised no one mentioned the biggie, and that would be: break dancing.
At least when I was a kid in the '80s, it actually meant something, not like it does today.
And, I was also into temporary tattoos, those styrofoam airplanes that cost approx $0.25, Garbage Pail Kids cards, Wacky Packages.
Would you believe, marbles got really big at my elementary school, I remember only two people had them one day, and then the next day everyone had them.
There are a lot of other things as well that I was into that were popular in the '80s, like: fluorescent shoe laces.
Guild_Navigator
Pre-washed jeans in the late 80s.

Good Lord...
In Canada, I know they used to call them "stone washed" jeans. And, yes, even if the jeans weren't stone washed, we still ripped the knees.