Hi Catherine,
You would want to create a Project report to show this information. Here are the report details I would include:
Grouping: Category > Name
Columns (View): Project Name, Project Owner, Project % Complete, Project Category Name
This should display how many projects have been created in the system, grouped by their Custom Form. This can be useful to determine projects with no custom forms or forms with low usage that could potentially be deleted or archived.
Note: Projects can have multiple custom forms attached. Groupings will be based on the "First" custom form attached.
Good luck! If you have any questions as you create your report, please don't hesitate to contact Support!
Best,
Hannah