Best answer by dan_ahrens
You can't do this in a simple report, as the SponsorTracking object would only have records for Accounts that have a tracked sponsor.
One way to solve for this would be to build a bionic rule that would aggregate (count) the number of contacts in the SponsorTracking object - so that you'd get a numerical value for each Account and then merge that data with all of your Accounts. Any accounts that have a tracked sponsor would have a numerical value >0 while any that do not will have a null value for that aggregation.
You can then run this report as a test and then view the execution results to download the data (equivalent of running a report to get this exported data): https://support.gainsight.com/Rules_Engine/Admin_Guides/Scheduling_Rules#Run_Now