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.

Bitcoin Cash SV is a cryptocurrency that was created as a result of a hard fork of the Bitcoin Cash blockchain that occurred on November 15, 2018. The central issue that led to the hard fork of Bitcoin Cash was a debate among prominent members of the Bitcoin Cash community regarding block size. A larger block size can improve transaction times, but also lead to greater network centralization. Roger Ver, an influential cryptocurrency advocate, was one of the central figures in favor of keeping the smaller 32 MB block size, while Craig Wright, the chief scientist at nChain, favored a larger 128 MB block size. The division between these two factions led to the hard fork that created Bitcoin Cash ABC and Bitcoin Cash SV.

Peercoin is the first Proof-of-Stake (PoS) cryptocurrency. It was created in 2012 and is one of the oldest and most reliable cryptocurrency networks in the crypto sector. The protocol was developed by Sunny King and Scott Nadel, both of whom are anonymous. Sunny King also created Primecoin and VEE.
Peercoin’s PoS consensus mechanism is now widely used in the blockchain space, and allows every network participant to be both a miner or an owner. The project is focused on creating a cryptocurrency platform that will be stable, secure, energy efficient, and distributed fairly.