Digital tickets for anything that uses tickets, deeds for transfer of real property, execution of contracts, etc.

Any use case in which some blob of data corresponds to an individually specifiable concrete thing is a suitable use case for NFTs.

The problem with the speculative frenzy a few years ago was that the NFTs in question did not convey ownership over anything -- people were trading the NFTs themselves rather than using them as deeds/contracts/tickets corresponding to some other external asset. If the NFTs were used to convey copyright ownership or exclusive usage rights to the underlying artwork, they'd have made a lot more sense, but as it played out, people were paying huge sums of money for what amounted to tickets to nowhere.