Is there some kind of graphic, perhaps a tree or something, that shows all of the inheritance for all of the controls and elements in UWP? Like starting with object as the root, and then extending to include everything from low-level classes like UIElement and Control and FrameworkElement to the high-level controls like Pivot, GridView, and Button, and including everything in-between like BindingBase, Panel, and ButtonBase?
There is no such graphic that describe all the UWP app controls' inheritance. There are so many Controls in UWP app, you can get the specific inheritance in the control's document. If you want to know all the relationships, we can do it by ourselves from all the UWP control introductions.
In UWP, the Control class is the base class for many of the controls you add to an app and its UI, such as Button and UserControl, it also inherite from FrameworkElement, there is also a control TextBlock that inherites from [FrameworkElement] directly.
You can get a list by function of the common XAML controls you can use in your app, and see UI controls and classes that support existing and custom controls in Windows.UI.Xaml.Controls Namespace.