Denarius is a hybrid cryptocurrency with a consensus mechanism that combines elements of Proof of Work and Proof of Stake. Denarius' cryptographic hashing algorithm, Tribus, is ASIC resistant, and consists of three of the most secure and popular cryptographic algorithms. Denarius is named after a Roman coin that was widely used during the peak of the Roman Empire.

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.

Bitcoin Interest is a fork of the Bitcoin protocol that pays coin holders interest. Bitcoin Interest (BCI) allows users to securely earn interest payments without ever moving coins from their wallets. Bitcoin Interest's developers believe that paying interest, weekly or monthly, on inactive crypto-funds can benefit the entire cryptocurrency market by reducing volatility.
Bitcoin Interest (BCI) is the first cryptocurrency protocol to use the ProgPoW consensus algorithm. ProgPoW is a Proof-of-Work algorithm designed to reduce the centralizing tendencies of ASIC mining by making it easier for standard GPU devices to participate in the mining process.