The spectrum of what constitutes an NFT is quite broad. The more popular ones are along the lines of videos, music, and images. To give you an idea of how widespread the NFT umbrella is, consider that tweets can be classified as NFTs, allowing them to transition hands on the market just as other assets would.
For reference, Jack Dorsey, Twitter boss posted a tweet that reads “just setting up my twttr.” You may not think this anything special, but this tweet was sold as an NFT for a staggering $2.9 million.