CODE EXAMPLE FOR PYTHON

revit dynamo select all categories

import clr

# Import DocumentManager and TransactionManager
clr.AddReference("RevitServices")
import RevitServices
from RevitServices.Persistence import DocumentManager

# Import RevitAPI
clr.AddReference("RevitAPI")
import Autodesk
from Autodesk.Revit.DB import *

doc = DocumentManager.Instance.CurrentDBDocument


OUT = [i.Name for i in doc.Settings.Categories]