Robinhood - Free stock trading service.
Alpaca - Open links from Slack via desktop apps: Notion, Spotify, Zoom, Miro, Telegram, Airtable, Figma and VK.
Rally Rd. - Invest in blue-chip classic cars like stocks
Bullish.email - The Stock Market in your inbox every morning
Qooore - Investing app for hypebeasts
StockData.org - Free real-time, intraday and historical stock market, crypto and forex JSON APIs.