Espresso is a global confirmation layer that provides L2 chains with fast, reliable transaction confirmations backed by BFT consensus. Espresso's confirmation layer can prevent sequencer equivocation, protect against reorgs, and reduce finality risk for solvers in intent-based systems. Its versatility means chains can also use it as a decentralized sequencer and low-cost data availability layer.

Aztec Network is the first private ZK-rollup on Ethereum, enabling decentralized applications to access privacy and scale. Its industry-standard PLONK proving mechanism is used by the leading zero-knowledge scaling projects, ensuring the security of its rollup.

Axelar is a decentralized cross-chain communication network, aiming to level-up interoperability in Web3 by connecting heterogeneous blockchains and enabling asset mobility and program composability in an optimized way for both builders and end-users. The two layers of Axelar are the network and the API above it. At the core of Axelar is a permissionless overlay network that provides Turing-complete cross-chain communication through proof-of-stake and permissionless protocols. On top of the network are APIs and protocols, an application-development layer that developers use to compose across any number of chains. Once integrated, all new interconnected blockchains become interoperable with the application, resulting in limitless network effects.

Penumbra is a secure, cross-chain network that enables anyone to securely transact, stake, swap, or market-make without revealing their personal information to the world. Penumbra is designed to act as a secure zone for the entire Cosmos ecosystem, allowing for the recording of any type of asset in a single shielded pool. Cross-chain IBC transfers shield value when it moves into the chain and unshields it as it moves out to other transparent chains.

Aurora is an EVM built on the NEAR Protocol, providing a solution for developers to run their apps on an Ethereum-compatible, high-throughput, scalable, and future-proof platform, with low transaction costs for their users.

Aleo is a developer platform for building fully private, scalable, and cost-effective applications. It uses zero-knowledge cryptography to move smart contract execution off-chain, enabling a diverse range of decentralized applications that are both entirely private and can scale up to thousands of transactions per second.

zkSync is a Layer-2 scaling solution that preserves the security properties of the underlying blockchain by leveraging the latest generation of succinct zero-knowledge proofs. All funds in zkSync are held in a smart contract on the mainchain, while computation and storage are performed off-chain. For each Rollup block, a state transition zero-knowledge proof (SNARK) is generated and verified by the mainchain contract. This SNARK includes the proof of the validity of every transaction in the Rollup block.