A script something like what is described in this blog post could potentially fit the bill - it'll just run recursively on a given share/directory and give you the list of files that fit your definition of "cold/archive/infrequent" and also the total size of all of the files that fit the criteria.
As far as I know, inactive data reporting will only identify the total amount of data that is considered inactive, not necessarily the files themselves.
Inactive Data Reporting First available in ONTAP 9.4, inactive data reporting (IDR) is an excellent tool for determining the amount of inactive (cold) data that can be tiered from an aggregate. IDR uses a 31-day cooling period to determine what data is considered inactive. The amount of cold data that is tiered is dependent on the tiering policies set on the aggregate volumes. This amount might be different than the amount of cold data detected by IDR using a 31-day cooling period. • IDR is enabled by default on all SSD aggregates in ONTAP 9.6. • IDR is enabled by default on FabricPool aggregates in ONTAP 9.4 and ONTAP 9.5. • IDR can be enabled on non-FabricPool aggregates using the ONTAP CLI. This includes HDD aggregates starting in ONTAP 9.6.
• IDR cannot be enabled for situations in which FabricPool cannot be enabled: for example, root, aggregates, MetroCluster, and so on.