Non-Fungible Tokens or NFTs is a DApp implementation running on Ethereum.
Introduction
NFT Marketplaces
https://opensea.io/
https://rarible.com/
https://niftygateway.com/
https://superrare.com/
NFT Games
https://whimsygames.co/services/nft/
https://www.aakashg.com/2021/04/19/so-you-want-to-nft-your-game/
https://forum.unity.com/threads/nft-non-fungible-token-unity-and-nfts.1071932/
https://academy.stratisplatform.com/Developer%20Resources/Unity3D/NFTDeployMint/nft.html
https://medium.com/pinata/how-to-create-and-sell-unity-prefabs-on-ipfs-as-nfts-793352c62069
Courses
Introduction to NFTs: Non-fungible Tokens
References
ERC-721: Smart Contract Standard (https://erc721.org/)
https://kotaku.com/the-nft-market-has-collapsed-oh-no-1847021181
https://www.reddit.com/r/unity/comments/qozmwg/i_have_a_question_about_games_nfts_no_one_can/