Data binding system: A system links properties to the controls that modify their values.You can use them as is, customize them, or create your own controls. Controls: A library of standard UI controls such as buttons, popups, list views, and color pickers.It defines every UI you build with the UI Toolkit. Visual tree: An object graph, made of lightweight nodes, that holds all the elements in a window or panel.For more information, see the Comparison of UI systems in Unity. However, Unity UI (uGUI) and IMGUI are appropriate for certain use cases, and are required to support deprecated projects. Note: Unity recommends you to use UI Toolkit for your new UI development projects. If you have experience developing web pages or applications, your knowledge is transferable and the core concepts are familiar. UI Toolkit is inspired by standard web technologies. You can use UI Toolkit to develop custom UI and extensions for the Unity Editor, runtime debugging tools, and runtime UI for games and applications.

UI Toolkit is a collection of features, resources, and tools for developing user interface (UI).

Unity assets collection