Detail this asset from Unity Asset Store: Original Link
This is a paid asset, but now you can download PowerSprite Animator Free.
PowerSprite Animator v1.7.2 (Latest version)
PowerSprite Animator v1.5
A cracking fine tool for editing sprite animations! PowerSprite Animator works with Unity’s existing sprite system- it won’t mess with your existing work-flow, just make it super nice to preview and edit your sprite animations!
Forum Thread | 20 Second Overview Gif
Features:
– Quick and easy sprite animation editor
– No more adding objects to a scene just to edit an animation!
– Easily insert and delete frames, and tweak their order and duration.
– A lovely event timeline that makes animation events FUN.
– Add nodes/attachment points with ease!
– Supports both Unity Sprites and UI Images.
– If you want, play animations from scripts, bypassing mechanim altogether. Just like Nonna used to do!