As of yet there are two controls by Proposition One on the Unity Asset store.
First is the Tree View Control
This is a script-based Tree-View control that is created at runtime and features a large script library for interaction with the control. A demonstration video is available here:
The second is a fully customizable Tab Menu Control – You’ll never need to spend time designing or scripting one of these again – this package is designed for rapid set up of tab menus in the 4.6+ Unity UI system.
This control is an editor and script based control for easy set-up of tab menus taking out all the frustration and time lost of resizing buttons, stretching to proper fit, and scripting the swapping out of menus. It is designed to be versatile and to always look its best even when resized due to resolution differences or user resizing (there is no native way to resize the module by the user at runtime through mouse controls, one must have their own GUI resizing class to implement this functionality – but it is designed to adapt itself when it is resized by any means). The extended demonstration of the Tab Menu Control is viewable here:
Proposition One 