Polkadot
Provides interconnectivity and interoperability between blockchains, by enabling independent chains to securely exchange messages and perform transactions.
Kusama
Kusama has almost the same codebase as Polkadot. Experimental blockchain designed to provide a massively interoperable and scalable framework for developers.
Moonbeam
Ethereum-compatible smart contract parachain on Polkadot. Moonbeam makes it easy to use popular Eth dev tools to build or redeploy projects in Substrate.
Bifrost
Bifrost (BNC) is a Polkadot-based parachain designed to provide liquidity and staking without nominating delays, allows users to deposit their staking tokens.