NEM is a cryptocurrency and blockchain platform that allows multiple ledgers on the same blockchain. NEM Smart Assets are used to create mosaics for any asset. Transaction fees are paid with NEM's native currency, XEM. NEM originally began as a community-oriented cryptocurrency that was built from the ground up in the Java programming language.
NEM's goal is to achieve widespread distribution through improved scale and speed. It pioneered several blockchain features such as its proof-of-importance (POI) consensus algorithm, encrypted messaging, a unique reputation system, and multi-signature accounts.
NEM is also developing a commercial blocckahin called Mijin, that is currently being tested by several companies and financial institutions.
In early 2018, approximately $400 million worth of XEM were stolen from a Japanese exchange called Coincheck, that was the victim of huge hack. The exchange failed to implement proper security for this coin protocol, and the hackers only stole XEM coins as a result. Instead of creating a fork to deal with this issue, NEM set up an automated tagging system that flagged these funds. NEM then stopped tracking these stolen coins

Primecoin is a cryptocurrency based on finding prime numbers. Identifying prime numbers plays a central role in cryptography. Primecoin's unique Proof-of-Work (PoW) consensus mechanism is able to increase transaction speeds and improve energy efficiency.
The network searches for special prime number chains known as Cunningham chains and bi-twin chains, which are of interest in mathematical research.

EOS is a blockchain development platform created by Block.one. Its goal is to become an all purpose operating system for blokchain applications. EOS allows developers to make underlying blockchains and create decentralized application more easily. It was designed from the ground up, to be more scalable and faster than other blockchain platforms. This allows for greater throughput, with more transactions per second, and much lower transaction fees. EOS tokens serve as the native currency. The network has a Delegated Proof-of-Stake (dPoS) consensus mechanism. Transactions are verified by 21 block producers that are chosen through a voting process that is designed to encourage community participation.