Arbitrum

Arbitrum: Arbitrum is a "Layer 2" to the Ethereum blockchain protocol being led by Offchain Labs and the founding team of Ed Felten, Steve Goldfeder, and Harry Kalodner. Arbitrum is utilizing an Optimistic Rollup as opposed to ZK Rollups in order to achieve its speed and scale.  It is a full EVM (Ethereum Virtual Machine) compatible protocol designed to scale any Ethereum Contract.

Check them out at https://offchainlabs.com/ or try out their Ethereum to Arbitrum bridge https://bridge.arbitrum.io/

Summary

Arbitrum