Bitcoin uses peer-to-peer technology to operate with no central authority or banks; managing transactions and the issuing of bitcoins is carried out collectively by the network. Bitcoin is open-source.
Bitcoin is an innovative payment network and a new kind of money.
Ethereum is a decentralized software platform that enables SmartContracts and Distributed Applications; it is additionally a virtual currency.
Litecoin (LTC or Ł) is a peer-to-peer cryptocurrency and open-source software project released under the MIT/X11 license. Litecoin was an early bitcoin spinoff or altcoin.
0x is an infrastructure protocol that allows users to easily trade ERC20 tokens and other assets on the Ethereum blockchain.