Cardstack is a blockchain technology company that is developing an open-source framework and consensus protocol to make blockchains more usable and scalable. Their goal is to create a decentralized modular smart contract ecosystem. The Cardstack network is powered by the Ethereum-based CARD token.

TrueChain is developing a secure and scalable blockchain platform with a strong developer community. TrueChain hopes to improve upon current platforms with a hybrid consensus protocol called Minerva. This hybrid model will combine a consensus mechanism based on Practical Byzantine Fault Tolerance (pBFT) with a FruitChain-based Proof-of-Work protocol. Fruitchain is designed to minimize the incentives of mining pools by decreasing the variance of mining rewards; making the network more decentralized.
TrueChain's architecture also hopes to improve transaction times and reduce fees, by including a sharding mechanism that is locked to Gas fees. The first use cases for their platform will be digital advertising solutions.
The company is backed by several large Chinese blockchain companies, including ZB.com; one of the largest cryptocurrency exchanges. digital advertising industry

Chromia is a relational blockchain platform that is designed to be both a blockchain and a relational database. Chromia was created by a Swedish development company called ChromaWay, with the intention of combining the advantages of a blockchain's transparency with the benefits of a relational database system, such as data independence and reduced redundancy.