tkinter is the standard Python interface to the Tk GUI toolkit and the de-facto standard for Python user interfaces. However, developing interfaces by hand is slow and error-prone. Peter Reutemann will demo the pygubu designer, which makes creating tkinter interfaces not only faster, but also easier to create good looking ones.
Large number of example UIs available:
https://github.com/alejandroautalan/pygubu-designer/tree/master/examples
Video: