I have a large data directory - almost 2 tb of data. How do I use GIS to create a list of all my datasets?
There is no builtin tool to do this. You would have to script something.
Arcpy's da.Walk http://pro.arcgis.com/en/pro-app/arcpy/data-access/walk.htm
in conjunction the 'Listing...' options http://pro.arcgis.com/en/pro-app/arcpy/functions/listdatasets.htm
will provide you the basic to get the information that you need.
You may be able to use my addin
Python addin for data inventory and “broken-link” repair.
If you are using Pro, (and maybe Desktop 10.5+) the addin itself might not load, but you can unzip the .addin and access the toolbox and scripts.
Retrieving data ...