I found this really useful page on bitbucket of a collection of extension scripts made from various of people to enhance your Unity UI experience. Organized by this guy to keep it so neat and simple in your projects
Including Radial menu like "rachet and clank", SelectionBox for a RTS game where you can drag a selection of characters, simple ToolTip box, and draggable windows!
He has a youtube page that showcased many of these scripts here, Take a look:
I've been using one that's very helpful for inventory list with a vertical scrollbar. It's autoscrolls to whatever you select. Great for gamepad's d-pad support or arrowkeys XD
Spreading the love for all the devs!