Apart from normal gaming add-ons, domains, art, digital art, real estate, etc., what else can the NFTs be used for? What exclusive stuff would you like to sell through NFT's?

You can make as many copies of a digital file as you like, including the art that comes with an NFT. NFTs, on the other hand, are designed to give you something you can’t copy: ownership of the work. In terms of physical art collecting, anyone can buy a Monet print, but the original can only be owned by one individual.