The Alert report will return a list of all alerts during a period - either every individual alert that matches the parameters, or a count of the number of times each alert occurred.

To define the set of alerts included in the alert report, fill out the Alert Parameters section:

As for other alert filtering, both regex and glob expressions are supported when specifying hosts and groups.

If "Only include active alerts?" is selected, then the report will include only those alerts that are still alerting (not those that have cleared.)

If "Summarize alert counts" is selected, then a column is added to the report detailing the frequency with which that alert occurred during the report period, and this alert count is available as a sorting metric for the report. This is very useful for determining the top sources of alerts, to focus on either correcting issues or alert tuning.