This is a paid asset, but now you can download Drag & Drop Pro Free.
Detail this asset from Unity Store: Original Link
Drag & Drop Pro v1.84 (Latest version)
Customizable plugin to make your own drag and drop system.
Implement your game UI, inventories, etc by using Drag & Drop Pro plugin.
All kinds of Unity UI elements can be used as an object or a panel.
Features :
– Full C# source code.
– Easy setup and well-written documentation.
– Mobile supported.
– Save system.
– More than 10 customization tools : Look at the screenshots please.
– Filter panels tool : To specify that which objects can drop on which panels.
– Multi Object tool : Allow to drop more than one object on a panel.
– Panel Object detection : To know which object is on the target panel.
– AI system : By using this, you can simulate the drag and drop system without user control.
– TextMesh Pro supported.
– Screen Space Camera & World Space Canvas render modes are supported.
– Events management.
– Demo scene included.
etc…
Some of new features have been shown in third video.
Unity 5 & Unity 2017 versions are supported.
Please note : This plugin isn’t useful for dragging and dropping between the contents of a Scroll View or 3D objects.
Car & football (soccer) game assets that available in second video are not included.
If you have any question about the plugin, feel free to contact me.
Don’t forget to write your review and share your experience with other users.