GEMS and GODS are ERC-20 tokens used as in-game currency for Guild of Guardians and Gods Unchained. The IMX token is the utility token of the Immutable X Layer 2 protocol, which solves Ethereum's scalability issues. The key difference is that IMX enables fast and cost-effective transactions, while GEMS and GODS are specific to their respective games.
To see the list of supported ERC-20 tokens on Immutable, see our tokens API.