Ethereum Classic is the original protocol of Ethereum. As a result of the massive hack on the Ethereum-based DAO, in which around 14% of all ETH in circulation were stolen, a hard fork was proposed to return the stolen funds to their owners. This caused an ideological split revolving around the question of changing previous transactions in the blockchain. Some Ethereum holders rejected the hard fork, and decided to keep using the original protocol, based on the principle that the blockchain is immutable, and cannot be changed.

Diamond (DMD) is a Proof-of-Stake coin focused on scarcity. Their marketing materials emphasize the limited circulation of the coin, and the benefits of the network's incentivized cloud mining system, which rewards users for contributing their computing resources.

Aurora is developing a blockchain platform that is based on a hybrid dPoS and BFT consensus mechanism. Aurora aims to improve overall blockchain performance with better transaction speeds and security features. Aurora has a multi-chain architecture and an Intelligent App Isolation system that are designed to allow for better smart contract execution. The network is currently powered by the Ethereum-based AOA token.