Optimism: Optimism is a Layer 2 scaling solution for Ethereum that uses Optimistic Rollups to increase transaction throughput while maintaining Ethereum's security and composability.

zkSync: zkSync is a Layer 2 scaling solution that employs zk-rollups to enable fast and low-cost transactions on the Ethereum network by aggregating multiple transactions into a single proof.

Arbitrum: Arbitrum is a Layer 2 solution that utilizes Optimistic Rollups to bring high throughput and low fees to Ethereum, allowing developers to deploy scalable dApps.

Polygon (formerly Matic): Polygon provides a Layer 2 scaling solution for Ethereum, offering various sidechains and PoS networks to enhance scalability and enable faster transactions.

StarkWare: StarkWare employs zk-rollups to bring scalability and privacy to Ethereum and other blockchains, allowing for efficient and private transactions on Layer 2.

Loopring: Loopring is a Layer 2 scaling solution that utilizes zk-rollups to enable high-throughput and secure decentralized exchanges on the Ethereum blockchain.

Hermez Network: Hermez Network is a zk-rollup solution that focuses on scaling Ethereum for payments, offering fast and low-cost transactions by aggregating transfers.

Celer Network: Celer Network is a Layer 2 scaling platform that enables off-chain scaling solutions, allowing users to build and run highly scalable dApps.

ZKSwap: ZKSwap is a Layer 2 decentralized exchange that uses zk-rollups to provide fast and gas-efficient trading on the Ethereum blockchain.

xDai Chain: xDai Chain is a Layer 2 sidechain of Ethereum that utilizes a stablecoin (xDAI) for fast and inexpensive transactions, suitable for various applications.