At the moment, the main NHL NFT platform is NHL Breakaway, which offers officially licensed NFT digital collectibles powered by NHLPA, NHL Alumni Association, and the NHL itself.
The NHL partnered with Sweet, a non-fungible token distribution platform, to create its NFT marketplace and collections of NFTs.
There may be other platforms that offer hockey-themed NFTs or other forms of digital collectibles, but to the best of my knowledge, NHL Breakaway and Sweet are the main NHL NFT platforms at present time.