BitShares is a blockchain platform designed to assist the unbanked. It offers both banking and exchange services. Bitshares was originally launched in 2014 by Dan Larimer, an influential blockchain developer that has also worked on EOS and Steemit. It is a community run open source project.
Bitshares' goal is facilitate greater access to financial services. The Bitshares exchange is a decentralized platform that was designed to be scalable and ensure low transaction fees.
Bitshares has a delegated Proof-of-Stake (PoS) consensus algorithm. Aside from a decentralized asset exchange, it also offers users the ability to issue their own assets, price-stable digital currencies, and flexible crypto payment options.
The Bitshares decentralized exchange and banking ecosystem is powered by the BTS token.

Synthetix, previously known as Havven, is developing a decentralized exchange that will allow users to trade a variety of collateralized stablecoins and commodities. The Synthetix network is built on Ethereum, and is powered by the SNX token, which works together with the Synth token to provide traders with opportunities to buy and sell assets on the Ethereum blockchain, through a distributed collateral pool.

0x is a decentralized exchange built on the Ethereum blockchain that allows for ERC20 tokens to be traded. 0x hopes to serve as a building block for creating decentralized exchanges.
It is an open-source system of smart contracts that acts as a platform for those wanting to build with the 0x protocol. Augur, Aragon and several other projects are using 0x, at the moment.
The 0x protocol addresses some of the common issues that plague other decentralized exchanges. 0x is faster, more liquid, and less expensive to run. Its speed is due to reduced blockchain congestion. This is achieved by moving all transactions off of the blockchain and then verifying them. This move, also allows for the elimination of transaction fees by reducing the reliance on the blockchain. 0x doesn’t charge fees of any type to use the protocol. However, Relayers that create their own decentralized exchange can charge fees.
The 0x Project uses the 0x Ethereum token, known as ZRX, that allows users to pay Relayers’ transaction fees. It is also a decentralized form of governance for the 0x protocol system. Anyone holding ZRX can give input about improving the protocol.