NetSpeedMonitor - NetSpeedMonitor is a lightweight Network Monitoring Toolbar for your Windows Taskbar
Zabbix - Track, record, alert and visualize performance and availability of IT resources
NetWorx - NetWorx is a simple and powerful tool that helps you objectively evaluate your bandwidth situation.
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.
GlassWire - Visualize network activity in detail, get notified when new apps access the network, look out for...
Prometheus - An open-source systems monitoring and alerting toolkit.