Mustache.js - Minimal templating with {{mustaches}} in JavaScript - janl/mustache.js
Unity - The multiplatform game creation tools for everyone.
EJS - An open source JavaScript Template library.
Godot Engine - Feature-packed 2D and 3D open source game engine.
FLAVE - Flave was created to bring ASP.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.