This is a paid asset, but now you can download Very Animation Free.
Detail this asset from Unity Asset Store: Original Link
Very Animation v1.2.10 (Latest version)
Very Animation v1.2.8
Very Animation v1.2.5
Very Animation v1.1.16
Very Animation 1.1.10p01
Unity 2020.1 Ready
About
This is an asset for editing animation in Unity.
You can modify animations and create new ones with Unity.
It is possible to directly edit Mecanim Humanoid animation, which is usually difficult to edit with Unity.
Tools such as mirroring animation creation and key frame reduction are also implemented.
Features
– Compatible with editing Humanoid and Generic animation.
– Legacy animation is also supported.
– It supports animation editing while editing Timeline.
– Collada Exporter
– The source code is all C#
– All source code is included