BurstCoin is a cryptocurrency with a Proof-of-Capacity (PoC) consensus algorithm. Unlike most other cryptocurrencies, Burst's architecture uses a Tangle (similar to IOTA) instead of relying on a blockchain. It also utilizes ring signatures and other features, in what is called the Dymaxion. The Dymaxion implements layers of tangle-based lightning networks on top of the Burst blockchain. Each of these payment channels is opened in the form of a standalone colored tangle. Burst is also developing atomic cross-chain transactions (ACCT), that will allow for full decentralized trading between two cryptocurrencies.

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.

Peercoin is the first Proof-of-Stake (PoS) cryptocurrency. It was created in 2012 and is one of the oldest and most reliable cryptocurrency networks in the crypto sector. The protocol was developed by Sunny King and Scott Nadel, both of whom are anonymous. Sunny King also created Primecoin and VEE.
Peercoin’s PoS consensus mechanism is now widely used in the blockchain space, and allows every network participant to be both a miner or an owner. The project is focused on creating a cryptocurrency platform that will be stable, secure, energy efficient, and distributed fairly.