Creating list of unused table values

I have a report template in which auditors report failures of a list of criteria. Each criteria may fail multiple times, but some may not fail at all. The template has a sheet with a table of criteria, and the results sheet uses dropdowns driven by that table. I've been tasked with adding a list of "passed criteria" to the report, and so I'm looking for a formula that would compare the criteria chosen in the dropdown with the full table, and would list those not appearing on the results sheet.

I know I can use COUNTIF to count instances of a value, but I need to list unused values.