Vitae is a Proof-of-Stake (PoS) blockchain platform that is a fork of PIVx. It is based on Blackcoin's PoS protocol. The company's marketing materials claim that its focus will be on facilitating social rewards and global prosperity, but they do not provide any specifics about what will distinguish them from other networks. It is powered by the VITAE coin.

Fiii Coin is developing an ecosystem designed to promote the wide spread adoption of a variety of cryptocurrencies. Their payment terminal will be compatible with wide range of cryptocurrencies, and will be comprised of a wallet, exchange, and DApp development plugins. The Fiii blockchain has a Delegated Proof of Capacity (DPoC) consensus mechanism.

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.