HTMLCOIN is a Proof-of-Stake (PoS) blockchain platform focused on enabling the practical applications of smart contracts. The HTML blokchain is a hybrid of Ethereum and Bitcoin, and also combines elements of other blockchain infrastructures.

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.

BOMB is an Ethereum based token that is designed to be a deflationary cryptocurrency self-destructing currency. The project is meant to be a social experiment and financial case study to determine the feasibility of a deflationary currency. There were originally 1,000,000 BOMB in circulation, and 1% of each transaction is destroyed.