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.

Sphere is a smart contract platform and peer-to-peer payment network. The network has a hybrid PoW and PoS consensus mechanism and is powered by the native SPHR token, which can be swapped for an ERC20 token over the Ubiq smart contract platform.

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.