Maricopa County, AZ, which would include knocking on doors and making sure the people that were listed as living there actual do and that they voted the way the ballot cast for them said they did:
https://theconservativetreehouse.com/2021/04/07/democrat-lawfare-group-including-perkins-coie-sends-legal-threat-to-group-auditing-maricopa-county-election/#more-210759