Simple Port Forwarding - Simple Port Forwarding works with WebPages and not directly with your router.
socat - socat is a relay for bidirectional data transfer between two independent data channels.
AUTAPF - Reliable TCP and UDP port forwarding for Windows.
PortMapper - Do you need to map a specific TCP or UDP port on your machine to another port on another machine?
Robusta Port Forwarder - This tool is created with the primary intention of making it easy to the end user to set forwarding rules in his router....
Komodia Relay - Free open source tool to perform TCP based session relay