NetSpeedMonitor - NetSpeedMonitor is a lightweight Network Monitoring Toolbar for your Windows Taskbar
Multiping - Get MultiPing Support. Network monitoring in 60 seconds. MultiPing provides a graphical view of network performance, monitors hundreds of targets, and sends automatic alerts..
NetWorx - NetWorx is a simple and powerful tool that helps you objectively evaluate your bandwidth situation.
SmokePing - Smokeping is a tool for measuring latency.
GlassWire - Visualize network activity in detail, get notified when new apps access the network, look out for...
Fping (open source) - fping is a program to send ICMP echo probes to network hosts, similar to ping, but much better performing when pinging multiple hosts.