Someone here brought up Mario toys from McD's. They had them in 1990. I had never even heard of Mario until I got the toys. Even then, it would be another six years until I ever played a Mario game and another seven until I had a Nintendo (but I did have Mario Teaches Typing on my Mac LC).
Back in the day when I still liked greasy fast food, I had quite a few of the McD's toys. I had the Mac Tonight toys and also the food changeables (the ones that went from food to dinosaurs). There were also the Halloween buckets (pumpkins, ghosts, and witches) that I accumulated in 1989 and 1990. They'd serve your burger and fries in this instead of a box. You could use it to trick-or-treat or you could use it as a decoration. Everyone in my neighborhood used to put them up on bushes or trees (we had like a dozen of them on a rhododendron). They've had buckets since, some of which even had cookie cutters on the top.
One of my other favorites was Hot Wheels. These used to come out every August (and I think they still are handed out). Of course, McD's also had the typical seasonal items (little garden tools, stuffed basketballs, the beach party toys that I used to use in my sandbox, etc).
At Wendy's, there was a series of mini Mr. Potato Heads that came out in 1988. I've NEVER seen these anywhere other than my house. I have about eight or so of them in a shoebox somewhere. No idea if they're rare or not.