Kind of a pedestrian use case, which might be good for flavoring, but you could make a sweet “air” hockey table out of them. I imagine there being a future version of air hockey that actually magnets in a vacuum. You could basically flavor it as truly frictionsless air hockey, with the games having the puck fly around at incredible speeds.

Assuming that cars, or the preferred method of transportation uses the magnets to get around, you could also have new kinds of Rollerblades and skateboards that use the magnets to travel the infrastructure. Maybe its something that only punk kids do by slapping stolen magnets on planks of wood. They can cause problems as they constantly get in the way of the car users.

You could also flavor the skateboards/ as a corporation backed cost cutting measure. The only people with magnet cars are the elite/ultra rich and everyone else can only afford a magnet scooter or whatever. If you want a really cynical world you could even give right of way to the magnet cars, so common folk would have to dodge them traveling at incredible speeds.

I think there are a ton more examples, but I bet, assuming the super conductor is reliably reproducible, that we will have crazier use cases within a decade IRL than we could dream up here. Probably some weird way to make sprinklers work better or something