The unique tool is great for removing duplicate items.
However, if wanting to identify and extract all items that have related duplicates (i.e. the unique item and the associated duplicates), I currently need to use a summarise tool with count, a filter tool to identify the duplicate items and join tool to link back to the original data set. It sometimes takes a few times to get the right combinations, and additional summarise and join tools are sometimes needed.
It would be great if there was a duplicates tool which worked like the unique tool (i.e. you can select the field to duplicate on) and pulled out the unique item together with the associated duplicates.