Robinhood - Free stock trading service.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Rally Rd. - Invest in blue-chip classic cars like stocks
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Freetrade - Invest in stocks & ETFs for free, get started in seconds.
Prometheus - An open-source systems monitoring and alerting toolkit.