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.

Celer Network is developing a layer-2 scaling platform that aims to enable fast and secure off-chain transactions and off-chain smart contracts. The Celer Network hopes to enable developers to create scalable DApps by increasing the off-chain functionalities of blockchains.

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.