netcat - Netcat is a featured networking utility which reads and writes data across network connections...
Unity - The multiplatform game creation tools for everyone.
PortMapper - Do you need to map a specific TCP or UDP port on your machine to another port on another machine?
Godot Engine - Feature-packed 2D and 3D open source game engine.
Komodia Relay - Free open source tool to perform TCP based session relay
Blender - Blender is the open source, cross platform suite of tools for 3D creation.