General Resources
From Spring
Textures
Texture Competition 0001 - Metal
Texture Competition 0002 - Camo
Texture Competition 0003 - Stone/Concrete
Climates
Quanto's Methane World Climate
Code
GPL Code Repository
The Millionth Monkey Gets Its Typewriter - Movement Optimization
Sounds
Freesound contains high amount of samples even complete ones that are uploaded by users and licensed under "Creative Commons License", which in short - "If you use the files you need to attribute the creator of the file (i.e. say who made it)." Creative Commons License
