Ancient Beast is one of the top open source games hosted on GitHub with both client and upcoming server. 
It will be all about the blockchain and web3, so while it introduces a lot of people to open source, it will introduce them to those world revolutionizing technologies as well.

Game will use web3 login providers (like MetaMask) for the online multiplayer game modes and make heavy use of blockchain for storing and verifying gameplay data, as well as deal with transactions and NFTs at some point.