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.

Harmony is developing an open consensus blockchain platform. Harmony's sharding-based consensus mechanism is designed to scale as the number of nodes increases in the network. Harmony aims to tackle issues related to scalability by optimizing across multiple layers in a way that will enable parallel transaction processing with reduced latency. Harmony is currently powered by the ONE token, which is built on the Binance blockchain.

Nethereum is an open source .NET integration library for Ethereum. It is designed to help developers easily integrate the Ethereum blockchain into their .NET applications. It consists of modular libraries for features that are covered are writing smart contracts, cryptographic wallets, DApps, and managing blockchain data.