I googled and search stackoverflow before asking this question
Answers that I don't expect:
wxWidgets is the best Python GUIUse TkInter (BIM) for GUI development.
Q. How to make a GUI without using any module/library? i.e make a GUI from scratch. Modules like tkinter not allowed.
The easiest GUI to make without "module/library" is a web-based one. I.e. generate HTML with Javascript from your Python code, and let the Javascript interact via AJAX with your Python app. This can be implemented without too much effort with just the standard Python library (and some JS code, of course), or with modules that don't require "heavy" installation of platform-specific extensions.
Python custom GUI