Binance - Cryptocurrencies exchange platform
Uphold - Move, convert, transact and hold any form of money or commodity. Instantly, securely and for free.
Robinhood - Free stock trading service.
Ripio - This exchange has very few options, however, it's one of your best options if you are in a South American country which is not supported by Coinbase.
Coinbase - Bitcoin, safe and easy.
BitStamp - Provide reliable and easy to use service for companies and individuals to exchange bitcoins.