TrumpCoin is a cryptocurrency that was created to support Donald Trump. Their marketing materials do not provide specific details about what they hope to achieve, or why they need a blockchain-based digital currency. TrumpCoin has a hybrid Proof-of-Work (PoW) and Proof-of-Stake (PoS) consensus mechanism.

Nimiq is a censorship-resistant cryptocurrency that is designed to run in the user's browser. Nimiq's focus is on usability and the browser first approach allows coin holders to participate in their payment network more easily. Nimiq uses a Merkle-based accumulator to store accounts and balances, and has a Non-Interactive Proofs of Proof-of-Work consensus mechanism.

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.