Are there any Python libraries for The Elm Architecture?

I don’t have a verified Python package name to recommend. If you look around, check whether a project clearly separates model, update, and view, and how it handles commands or other side effects. That should help distinguish a TEA-style library from a GUI toolkit with a different state model.

If you end up making your own, I’d keep the first version tiny: one state value, a message type, an update function, and a view function. Let Tkinter handle rendering and events, then add a consistent way to run effects only if your app needs them.