Arbitrum (ARB)

A layer built over Ethereum that moves execution into a separate environment and returns only the result to the main chain: transactions cost less, while security is inherited from Ethereum through a mechanism for challenging an incorrect state. The price of that model is time: withdrawing back by default waits out the challenge period. Development is led by Offchain Labs, and network parameters and treasury decisions belong to the ARB holders' DAO; applications port over with barely any code changes.