TinyWall - Lightweight and non-intrusive firewall
Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS
simplewall - Simple tool to configure Windows Filtering Platform (WFP) which can configure network activity on...
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Windows 10 Firewall Control - Windows 10 Firewall Control: simple and exhaustive solution for applications network activity controlling and monitoring.
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.