Major players and community upstarts alike are gunning for OpenSea. Can any of them claim the throne?In briefOpenSea is the leading NFT marketplace, handling billions of dollars’ worth of transactions a month recently.Many new marketplaces are launching to challenge OpenSea, including from major cryptocurrency exchanges.This spring’s NFT market boom put up massive figures, but it was nothing compared to the late summer resurgence, which led to nearly $10.7 billion of trading volume in Q3 alon...