The following are some the useful tools that are required:

• Image editor: Photoshop and Gimp both are good examples of programs that allow us to create 2D UI elements and textures for objects in our apps.
• 3D modeling software: 3D Studio Max, Maya, and Blender are all programs that allow us to make 3D objects that can be imported in Unity.
• Sound editing software: There are a few resources for free sounds on the Web. With that in mind, Sound Forge is a great tool for editing those sounds, layering sounds together to create new sounds.