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.

Qtum has been described as a hybrid between Ethereum and Bitcoin. Qtum is a smart contracts platform that places a strong focus on value transfers as well as decentralized apps. Qtum enables users to create smart contracts on the platform and conduct cryptocurrency transactions.
Qtum has a Proof-of-Stake (PoS) consensus algorithm. Several decentralized apps are already using the platform.

Telcoin is an Ethereum-based cryptocurrency that will be distributed by mobile network operators. Telcoin (TEL) plans on working with national telecom operators to distribute their currency. They hope that this distribution model will provide greater financial inclusion to un-banked communities, and will encourage cryptocurrency adoption. This is a similar strategy as MPesa, the mobile payment network created by SafariCom, that uses the telecom's provider's existing infrastructure to allow users to easily make payments with their mobile phones. Telecoin sees their platform as a complement to existing mobile money systems that will help drive cryptocurrency adoption.