Bitcoiin is a cryptocurrency that was created to address some of the issues that have plagued the original Bitcoin ecosystem. It's Proof-of-Work (PoW) consensus mechanism is designed to decrease transactions times and fees, as well as make mining rewards easier to earn.

ILCoin is a PoW cryptocurrency. Their goal is to become the first cryptocurrency that uses the SHA-256 encryption algorithm to be able to execute smart contracts. The ILCoin is traded on several exchanges under the symbol ILC.

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.