Running a report that’ll show all your suppliers and has an indication if TPAR was selected or not is unavailable. You can instead run a report that’ll show suppliers included in your TPAR. Here's how:
For additional details, please check out this article: https://quickbooks.intuit.com/community/Reports/How-to-run-a-Taxable-Payment-Annual-Report-TPAR/m-p/...
make yourself comfortable on posting here again if you need something else.
Unfortunately there isn't a report customisation setting that will show a list of suppliers which do not have TPAR ticked.
I would recommend you submit your use case scenario as Feedback within QuickBooks so our product team is aware and can improve our product for you. Here is how to do it: https://community.intuit.com/articles/1164890-how-do-i-submit-feedback.