Good timing, I just created a report for template usage this week for a cleanup effort I'm doing.
- Create a project report
- Grouping: Template >> Name
- Filter: Project >>Template ID >> Is Not Blank
- Run report and go to the Summary tab. You can then see the templates that were used
- For my cleanup effort, I am going to the usage list and compare to a list of all templates, and the ones that don't have a duplicate are ones that have never been used.