Redis - Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.
memcached - High-performance, distributed memory object caching system
Skytable - Skytable is a free and open-source realtime NoSQL database that aims to provide flexible data modelling at scale.
KeyDB - KeyDB is fast NoSQL database with full compatibility for Redis APIs, clients, and modules.
Bluzelle Decentralized DB - Bluzelle is a decentralized database powered by PBFT Consensus Engine.
Swarm City - Swarm City is a decentralized commerce platform.