When working with UI in Unity I am always missing basic design functionality so I don't have to jump into Photoshop for every single element and for all changes. Especially in modern design these tools are very easy to use as most Elements are composed of some simple shapes. As a first step I developed "Procedural UI Image" (http://u3d.as/mYk). It allows you to create shapes with rounded corners, border radius and other basics right inside Unity. All of that fully procedural (without generating image files).
Some of my customers mentioned that they needed gradients in their UI and how to best achieve this. Following the same principle I developed this asst. No need to switch into Photoshop or any other app and no image files generated.
If you have any questions or feedback about this. Feel free to contact me!