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.

Sphere is a smart contract platform and peer-to-peer payment network. The network has a hybrid PoW and PoS consensus mechanism and is powered by the native SPHR token, which can be swapped for an ERC20 token over the Ubiq smart contract platform.

Quantum Resistant Ledger is developing an enterprise blockchain platform that is designed to be secure against an attack from quantum computers. The Quantum Resistant Ledger (QRL) implements a more secure type of cryptographic signatures call XMSS. The network has a Proof of Stake consensus mechanism.