I keep a master project containing each grouping of connections terms, and seals options. All sunk into a harness that can be reported and copied into excel without a tool. It takes a bit but once set up they just need to be maintained and reported. Aside from that i have no other way of doing it. if you don't need the terminals or seals it is much easier because you don't have to provide an array of wire gauges to achieve your goal.
You can extract a list of part numbers from the Component Library very easily.
Open up Component Library. Open a Component Maintenance window. Click the search button to return a list of all the parts in the Library.
In the list of part numbers that is returned, Click Ctrl+A then Ctrl+C and paste the data directly into Excel. Note that it will take time to copy the data to the clipboard.
If you want to extract more information you will need to use an Excel Macro to read the XML file. There is an example Macro here: