OKCash is a Proof of Stake cryptocurrency that was released under the MIT licence.

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.

PLATINCOIN is a Proof-of-Stake coin that is minted instead of mined. Users participate in managing the network by renting hardware space from the project organizers for a period of 36 months. These computing resources will drive the PoS consensus, and the users that rent the hardware will be rewarded with newly minted PLC coins.