Gate.io is a crypto to crypto exchange based in the USA. It is an unregulated exchange and does not accept US clients. They offer one of the widest selections of tokens.

Trading Fee: 0.2%
Withdrawal Fee: 0.01 BTC, 0.03 ETH
Number of Tokens/Coins: 347

Gate.io has received many negative reviews regarding difficulties withdrawing funds.

Bittrex is one of the largest crypto to crypto exchanges. It offers a large number of trading pairs, but do not allow fiat to crypto trading. Bittrex has one of the largest trading volumes in the market.
It is a reputable exchange with good record on security and is also fully regulated. They provide two factor authentication as well as a number of other options to secure funds. They are United States based and are fully compliant with all laws.
They support more than 190 cryptocurrencies and have a dynamic platform. It’s a good option for both advanced and beginner traders; providing advanced tools like candlestick charts and crosshairs, but with a user-friendly interface that is very intuitive.
Trading Fees: 0.25%

Liquid is a blockchain platform that was created by the fintech company Quoine, that has a suite of blockchain powered financial services. Liquid is focused on providing liquidity to crypto industry. The platform offers a "worldbook" which is a multi-market order book that aggregates liquidity sources to one order book and supports trading in multiple currencies. Liquid has several features that are aimed at increasing the liquidity of crypto assets. The platform includes smart order routing, a currency conversion engine, fiat management, and other trading tools. Liquid is powered by the QASH token, which was released in an ICO that raised $105 million.