Here's an older post from @Doug_Den_Hoed__AtAppStore that has a solution for reporting on additional templates attached to a project. How can I run a report on "second" template used in a project? would be great if details tab showed ...
I added a few prompts to my report: project, program, portfolio, and group in case I want to know which template(s) were added to certain projects. I also collapsed the second grouping while creating the report so it's always collapsed.