Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download EZSprite Free.
EZSprite provides a simple solution for 2D sprite animation managment.
Use the provided Atlas Maker to easily create an atlas, then open up the EZSprite Animator and start animating in seconds.
Works with Character Controllers, Rigidbodies, GUI elements and more.
Comes with a low-poly plane for even more optimization. Compatible with C# and Java.