This is a paid asset, but now you can download Loading Screen Free.
Detail this asset from Unity Store: Original Link
Loading Screen v1.4.5 (Latest version)
Loading Screen v1.2.8
Loading Screen is drag and drop system that allow you to create beautiful and professional loading screen for your game, save the time to create your own and use this that is so simple to use, you only need one line of code for use, instead of SceneManager.LoadScene();.
– Full UGUI System.
– Smooth Transition between scenes.
– Asynchronous and Fake loading.
– Background Transitions.
– Game Tips system.
– Background sound with fade effect.
– One line of code to use.
– Loading Progress Bar.
– Loading Progress Text.
– Loading Progress Filled image.
– Display Scene description.
– Display Scene custon Name.
– Drag and Drop system.
– Fully and easy customizable.
– Easy extendable.
– 15 Ready made prefabs for use.
the background images and background audio of video is for demostration purpose only and not include in the package.