Robinhood - Free stock trading service.
Alpaca Trading API - Simple REST API for commission-free stock trading
Freetrade - Invest in stocks & ETFs for free, get started in seconds.
Robintrack - Discover trends in the popularities of stocks on Robinhood
Rally Rd. - Invest in blue-chip classic cars like stocks
Raiz - Invest spare change automatically from everyday purchases into a diversified portfolio.