Review Date: January 30, 2020 21:33:42
This is the most popular and largest NFT trading marketplace. I really do not know of any others, built specifically for Ethereum blockchain NFTs. Interesting note that not so long ago, the Splinterlands game, based on the Steem blockchain, minted their cards (NFTs) using Ethereum. And those were also available on OpenSea to trade. So OpenSea is like the crosschain marketplace for all NFTs.