Hi there! If you purchased the package, you should still be able to download it from the Asset Store in the Editor.
That said, as I have mentioned elsewhere, I actually work for Unity now and have improved some of the tools that were in this package and incorporated them into Unity proper. Depending what specifically you were interested in, it may be a better idea to
browse the Unity source and take a look (e.g., ArcHandle, JointAngularLimitHandle, PrimitiveBoundsHandle, and so on).