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.

Groestlcoin is a blockchain payment protocol with a number of technical innovations and an active developer community. Groestlcoin was the first coin that activated SegWit and supports the Lightning Network. Transaction fees are very low and it claims to have instant payments. It is also one of the only coins that can be sent over SMS.
Groestlcoin's active developer community has made the payment protocol very adaptable, and it a popular coin among many crypto investors. Groestlcoin has an ASIC resistant Proof-of-Work consensus mechanism.

PIRL is a community based blockchain project focused on making cryptocurrencies more accessible. It was the first blockchain to introduce an Ethash-based masternode. Their goal is to develop a comprehensive DApps hosting infrastructure that will be easy to use. Their Poseidon platform is designed to be an on ramp for users without any technical knowledge. PIRL's multi-tiered masternode network has an ASIC-resistant Proof-of-Work (PoW) consensus mechanism, and is powered by the PIRL coin. The company plans on developing features, such as: decentralized file storage, messaging, and escrow services for payments.