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.

ZCoin is a privacy focused cryptocurrency built on Ethereum. The ZCoin protocol enables anonymous transactions with cryptography that utilizes Zero-Knowledge Proofs (ZKP). ZCoin increases privacy on their network by using a coin-mixer contract that wraps transactions in a serial number and destroying wrapped coins once they have been redeemed.
Zcoin was the first cryptocurrency to use a Merkle Tree Proof (MTP) as its proof of work algorithm. Merkle Tree Proofs are an innovative solution to achieving network consensus, and can increase transaction time while reducing the centralizing tendency of ASIC mining.

Nasdacoin is developing a blockchain with a hybrid consensus mechanism that combines elements of Proof-of-Work (PoW) and Proof-of-Stake (PoS). Nasdacoin uses the Scrypt hashing algorithm and is powered by the NSD coin. The company plans on developing a comprehensive ecosystem with a native exchange, wallet, App, and marketplace. They also plan on allowing Nasdacoin holders to transfer their NSD balance to a Visa card that can be used anywhere.