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.

Lightning Bitcoin is a cryptocurrency protocol with a DPoS consensus mechanism. It is a hard fork of Bitcoin that was created with the goal of improving transaction speeds and scalabilty. Lightning Bitcoin's on-chain governance system enables LBTC holders to vote for the blockchain improvement proposals and the delegates who maintain the network as Lightning Nodes. Lightning Bitcoin is not related to the Lighting Network, which is an off-chain protocol built on the Bitcoin blockchain.

QChi is an Ethereum-based token with no clear benefits. Their marketing materials do not provide any specific information about their roadmap or what advantages it offers compared to other cryptocurrencies.