TronClassic

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.

eXPerience Chain is a community focused cryptocurrency with a unique Proof of Stake consensus mechanism. The team behind the project is based in South Korea. Their consensus mechanism is called Age Burnable PoS (ABPoS).