Fiii Coin is developing an ecosystem designed to promote the wide spread adoption of a variety of cryptocurrencies. Their payment terminal will be compatible with wide range of cryptocurrencies, and will be comprised of a wallet, exchange, and DApp development plugins. The Fiii blockchain has a Delegated Proof of Capacity (DPoC) consensus mechanism.

Spendcoin is an open-sourced cryptocurrency designed for the Cross Ledger Ecosystem, which includes the Spend App and the Blockchain University. The project is run by the Spend Foundation. Their network is currently powered by the Ethereum-based SPND token. Users receive tokens for performing tasks in the Spen ecosystem.

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.