SIBCoin is a Proof-of-Work coin that was originally based on the same code as the Dash blockchain. SIBcoin was developed by a team of cryptocurrency enthusiasts in Siberia and it has gained a significant following in Russia.

Mindexcoin is developing a universal payment platform powered by the Ethereum based token, MIC. Their marketing materials do not clearly outline any unique selling points, or advantages, that it will provide compared to other blokchain-based payment platforms.

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.