...
Recently updated: Reports are sorted based on how recently they have been edited, with the most recently edited reports at the top of the list.
Name: Reports are sorted by name in alphabetical order from A to Z by nameZ.
Recently ran: Reports are sorted based on how recently they've been run or rerun, with the most recently run reports listed first. For example, if you rerun a report that you've generated in the past and then sort the list by Recently ran, it will appear at the top of the list.
Recently created: Reports are sorted based on how recently they've been created, with the most recently created reports listed first.
Recently viewed: Reports are sorted based on how recently they've been viewed, with your most recently viewed reports listed first.
...