Hi @ wenwang1,
Well probably the only option will be to combine multiple queries from various reports into one more complex query, e.g using JOINS or UNION.
Nevertheless depending on the nature of queries, you are using in specific reports, this could only reduce number of reports but not to aggregate everything into one.
What you could consider as an alternative, is to develop custom report using Manage Controlled Processes from ACS Commons,
Sample report implementation you can find under:
This will give you an idea how you can start, if you would decide to create custom Process Definition to generate a report.