Unity UI Pack

The Unity UI Pack is a set of game assets designed to help you easily create user interfaces. This collection of C# scripts, sprites, and animations are created to make your Unity UI experience easier. These include:

• 25 2D textures to use for buttons, sprites, and decoration. It also comes with the 25 textures as PNG images outside of the main executable Unity Package
• 5 C# effect scripts. These include glitching, rainbow, 3D spinning, floating, and shake/spin effects.
• 3 sets of button animations. These can be added to any UI button object to make it do things when it's highlighted, clicked, selected, and disabled.

Before you purchase the pack, you can also check out the demo, which includes one set button animations, a glitch effect script, and an X icon, so basically one thing from each of the sections in the main package.

To import into a project, go to Assets>Import Package>Custom Package, and then select the UnityUIPack file in your downloads.

More info in this setup/use tutorial: