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.

NavCoin is a community-driven digital currency built on an open-source,Proof-of-Stake (PoS) blockchain. The project has an active development community, and places a strong emphasis on their user governance. NavCoin is developing a feature for its PoS consensus mechanism that will allow for cold staking. Users will be able to stake their coins while keeping them offline.

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.