In the main, you would be looking at segmentation (already covered), service types, customer types, reasons codes, statistics, screens, report types, exports and document scripts. A lot of the statistical and object information should/could be made available by attaching data to the interaction, through your Routing Strategies.
As a cross-section, you could mix and match something like the following elements to show within example reports;
>>Type of Call: Inbound, Outbound, Internal, etc.
>>Type of Caller: Customer, Business Partner, etc.
>>Customer Value/Segment; High Value (HV), Medium Value (MV), etc.
>>Reason for Call; Technical, Financial, Business, etc.
>>Department; Customer Services, Retentions, Debt Recovery, etc.
>>Team: CS1, CS2, DR1, etc.
>>Aggregation: Hourly, Daily, Weekly, Monthly, Quarterly, Annually.
>>Statistic Types; Total Number, Total Time, Average Time, Maximum, Minimum, etc.
>>Report Displays; Tables, Pivot Tables, Charts, EIS, Reports
>>Report Table/Query Exports; .csv, .xls, .html, etc.
>>Report Types; Client/GUI, Web-Based, Broadcast or On-Demand
>>Report Scripts; pre-running scripts, scripts on start up, scripts associated with a button press, scripts on opening/closing EIS, etc.
- If you mix and match all of these, you'll probably have enough content to complete around about 4,000 report templates... lol
Hope this helps - and good luck!

Tony