re-wx is a library for building modern declarative desktop applications. It's built as a management layer on top of WXPython, which means you get all the goodness of a mature, native, cross-platform UI kit, wrapped up in a modern, React inspired API.
Neukivy is a collection of neumorphic widgets built with Kivy. The library is currently in its initial development so there isn't much yet. But hopefully it will grow into a library you can use to easily create neumorphic UI in python.