You can, for example, check out KnownOrigin. It is a marketplace where you can discover and collect rare digital artwork. Only authentic and truly unique artworks are sold on KnownOrigin. It is secured by the Ethereum blockchain. You can also try Portion. The nice thing about Portion is that it allows anyone to be a collector. As you can manage your physical and digital collection in one place, it is easy to exchange crypto for art and other collectibles.