The most expensive NTF token is the one that the crypto community knows about. It is enough to promote the picture on Twitter 
Founder Cat #18 Last sold for 253 ETH
https://opensea.io/assets/0x06012c8cf97bead5deae237070f9587f8e7a266d/18
Last sold for 246 ETH
https://opensea.io/assets/0x06012c8cf97bead5deae237070f9587f8e7a266d/1
See how many tokens are constantly being sold
https://wax.io/blog/round-up-wax-is-the-king-of-nfts-heres-why
Founder Cat #18 Last sold for 253 ETH
https://opensea.io/assets/0x06012c8cf97bead5deae237070f9587f8e7a266d/18
Last sold for 246 ETH
https://opensea.io/assets/0x06012c8cf97bead5deae237070f9587f8e7a266d/1
See how many tokens are constantly being sold
https://wax.io/blog/round-up-wax-is-the-king-of-nfts-heres-why
This was surprising to me, so indeed crypto has entered the world of art, I think some expensive NFTs have their own uses such as mining, game, or crypto-related.
The Nine Most Innovative Crypto Artists of 2020
In 2020, crypto art based around non-fungible tokens has exploded. We've spoken to nine crypto artists working at the bleeding edge of NFTs.
https://decrypt.co/52447/the-nine-most-innovative-crypto-artists-of-2020
Try to imagine the prospects of this market in 10 years..