The PlayFab API can be made to support a variety of languages with the SDKGenerator.
So I created a GDScript version of PlayFabSDK based on PythonSdk.
You can find it here:
https://github.com/MizunagiKB/PlayFab_GDScriptSdk
There is no reference available, but a sample project for GodotEngine 3.2 is included.
Notes.
This is just a port and has not been tested.
The PlayFab Party function is a different library and cannot be used from this SDK.
I hope this will be of some help.