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.

Nasdacoin is developing a blockchain with a hybrid consensus mechanism that combines elements of Proof-of-Work (PoW) and Proof-of-Stake (PoS). Nasdacoin uses the Scrypt hashing algorithm and is powered by the NSD coin. The company plans on developing a comprehensive ecosystem with a native exchange, wallet, App, and marketplace. They also plan on allowing Nasdacoin holders to transfer their NSD balance to a Visa card that can be used anywhere.

Gulden is a Dutch cryptocurrency based on a native blockchain with a Proof-of-Work (PoW) consensus mechanism. Gulden has gained traction in the Netherlands, where it can be used to make P2P payments, as well as send funds to an IBAN account. Gulden's marketing efforts emphasize the network's security and faster transaction times. Gulden's PoW² consensus combines aspects of PoS with PoW, and allows witnesses to add transactions to blocks after they have been mined. The network is powered by the NLG coin.