How to fetch the List of Layers and Services in ArcGIS SERVER using ARCPY?
alphabetical list of classes http://pro.arcgis.com/en/pro-app/arcpy/classes/alphabetical-list-of-arcpy-classes.htm
alphabetical list of classes http://pro.arcgis.com/en/pro-app/arcpy/functions/alphabetical-list-of-arcpy-functions.htm
there is stuff in the 'Describe' section, maybe AGOL and portal.
maybe some keyword might twig you needs.
Beyond that, if there is a tool in arctoolbox that you use, then the tool can be accessed through arcpy. Every tool has a code example and syntax at the bottom of their help topic
I have used this in the past: ListMapServices—Help | ArcGIS Desktop but it has been deprecated and you should now be using this: Scripting with ArcGIS REST API—ArcGIS Server Administration (Windows) | ArcGIS Enterprise . There are many samples available which you can adapt to your specific needs.
In Pro what is left is Updating and fixing connection properties and the Server tools and what is not available in server tools
So I take it this is not a question about arcpy at all.
Retrieving data ...