PAC coin, short for People’s Alternative Choice, is a cryptocurrency with a hybrid Proof-of-Work (PoW) and Proof-of-Stake (PoS) consensus mechanism. PAC Coin aims to encourage cryptocurrency adoption by improving usability and community governance. The network will rely on a system of masternodes to help verify transactions.

Primecoin is a cryptocurrency based on finding prime numbers. Identifying prime numbers plays a central role in cryptography. Primecoin's unique Proof-of-Work (PoW) consensus mechanism is able to increase transaction speeds and improve energy efficiency.
The network searches for special prime number chains known as Cunningham chains and bi-twin chains, which are of interest in mathematical research.

Ethereum is a blockchain-based computing platform and operating system whose core innovation is enabling smart contracts. Ethereum's smart contract functionality, and versatile scripting language, have made it the most popular network for creating decentralized applications. What makes Ethereum different from Bitcoin is that its primary purpose is to serve as a general purpose blockchain for creating DApps, and not as a payment network. Ethereum was created by Vitalik Buterin. It was launched in July 2015 and has become one of the most important blockchain platforms in the industry. Ether is the native currency of the Ethereum blockchain and can can be used as a transfer of value, as well as a form of compensation for mining. The Ethereum Virtual Machine (EVM) executes scripts using a network of public nodes. "Gas" is used as an internal transaction pricing mechanism that decides how resources are used on the network.