It would very useful to iterate over a list of issues and perform actions on them.
List could be provided from:
JQL search (allowing for smart values)
Issue Subtasks (though this can be done via jql)
Linked Issues (this can be done with jql)
Issues in Epic
Might need to fork the chain of execution as you may not want to perform all subsequent actions on the list. e.g. only send one email after iterating.