Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
NetSpeedMonitor - NetSpeedMonitor is a lightweight Network Monitoring Toolbar for your Windows Taskbar
HTTP Toolkit - Beautiful, cross-platform & open-source tools to debug, test & build with HTTP(S). One-click setup for browsers, servers, Android, CLI tools, scripts and more.
FreeMeter - Monitor network bandwidth (C#.NET 2k/XP+). Desktop and Systray graph.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface
NetTraffic - Essential network bandwidth monitor.