Windows support is currently still missing since I have no experience with Windows GUI frameworks.

Different options may be:

1. Use win32 and the Shell_NotifyIconW API documented here. Advantages: Can be used from pure Python code using ctypes.windll. See plyer for an example implementation. Disadvantages: Does not appear to support buttons.
2. Use Toast Notification API as documented here. Advantages: Simpler API. Richer UI with buttons etc. Disadvantages: Likely requires a package such as pythonnet with extension modules.