Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Proxycap - ProxyCap empowers you to divert your PC’s system associations through intermediary servers.
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Proxy SwitchyOmega - Proxy SwitchyOmega is the updated version of the proxy settings for easily switching and managing the multiple proxy servers and files within minutes.
Postman - The Collaboration Platform for API Development
FoxyProxy - FoxyProxy is a set of proxy and proxy switcher to reach the content of international market and easily switch between multiple proxies and proxy servers.