Robinhood - Free stock trading service.
Richie Invest - An app that lets you invest with your friends
Naga - Join our stock & crypto trading social network with over 1 million users. Copy other traders fully automatically with a free account and over 1,000 tradable assets.
Alpaca Trading API - Simple REST API for commission-free stock trading
Tradeary - Optimize your stock, crypto and forex trading profits
Robintrack - Discover trends in the popularities of stocks on Robinhood