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.

MonaCoin is the first alternative cryptocurrency developed in Japan. It is based on the popular Japanese character, Mona. MonaCoin has a Proof-of-Work (PoW) consensus mechanism and uses a version of the Lyra2RE mining algorithm that was first used by Vertcoin.
MonaCoin has an enthusiastic user base that has developed a variety of Mona-based web applications and services. MonaCoin holders also use the coin as a tipping system.

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.