BitcoinDark is a fork of Bitcoin with a poorly defined purpose and use case. BitcoinDark is based on the InstantDEX protocol, a decentralized exchange for BitcoinDark and other cryptocurrencies supported by the project. The platform is also supposed to include a Pegged Asset Exchange (PAX) to allow users to buy and sell pegged assets – including fiat currencies, commodities, ETFs, and stocks.
BitcoinDark is a Proof-of-Stake (PoS) currency that has gained a significant market cap, but the project has failed to show how its vision will be implemented or how it will add value compared to other blockchain projects.

PRIZM is an open-source cryptocurrency based on the NEXT core. The PRIZM architecture is built in JAVA. It has a Proof-of-Stake (PoS) consensus mechanism that varies slightly from other PoS algorithms. It is designed to be more resistant to attacks against the network. PRIZM has developed the concept of paramining, which helps the network achieve consensus and encourages community participation.

Bitcoin Cash is a cryptocurrency that was created as a result of a hard fork of the original Bitcoin blockchain that took place in 2017. Due to the open source nature of the Bitcoin protocol, and the lack of a central governing body to resolve disputes, the Bitcoin community became extremely divided about what to do about rising fees and slow transaction times. As the platform's transaction volume increased, and the associated fees to confirm them also increased dramatically, many people began advocating for a larger block size.
In mid 2017, a group of developers introduced segregated witness technology, or SegWit, that was designed to increase Bitcoin's scalability by moving some transaction details off of the blockchain. Segwit was meant to resolve the issues that revolved around the growing amount of transaction data, but many members of the Bitcoin community felt that it undermined the original vision outlined by Satoshi Nakamoto.
On August 1, 2017, they initiated a hard fork of the protocol that created Bitcoin Cash and implemented an increased block size of 8mb. At the time of the fork, bitcoin holders automatically became owners of the same number of Bitcoin Cash units. The increased block size led to faster transaction times and made Bitcoin Cash easier to use as a medium of exchange.