Robinhood - Free stock trading service.
Ellevest - An investing platform built for women
OptionsHouse - OptionsHouse is an online stock trading platform with an easy-to-use interface.
Alpaca Data API - Free real-time stock market data API
Entrade - Best Commodity Trading, Transaction, and Risk Management (CTRM)
StockTwits + Robinhood Integration - Zero commission trading directly from the StockTwits app