#{for links}
   ${Links[n].AppType}
   ${Links[n].LinkType}
   ${Links[n].Key}
   ${Links[n].Summary}
   ${Links[n].URL}
#{end}
 
or
 
#{for <VariableName>=LinksCount}
   Content and Linked Issue Mappings. Example: ${Links[VariableName].Field}
#{end}

#{for comments}
   ${Comments[n].Author} 
   ${Comments[n].AuthorFullName} 
   ${Comments[n].Body} 
   ${dateformat("dd-MM-yyyy HH:mm:ss"):Comments[n].Created}
   ${Comments[n].GroupLevel}
#{end}
 
or
 
#{for <VariableName>=CommentsCount}
   Content and Issue Mappings. Example: ${Comments[VariableName].Field}
#{end}

#{for subtasks}
   ${Subtasks[n].Key}
   ${Subtasks[n].Summary}
   ${Subtasks[n].AssigneeUserDisplayName}
#{end}
 
or
 
#{for <VariableName>=SubtasksCount}
   Content and Issue Mappings. Example: ${Subtasks[VariableName].Field}
#{end}

#{for components}
   ${Components[n].Name}
   ${Components[n].Description}
   ${fullname:Components[n].Lead}
   ${Components[n].Id}
   ${Components[n].ProjectId}
   ${Components[n].AssigneeType}
#{end}

#{for statusTransitions}
   ${StatusTransitions[n].Author}
   ${dateformat("dd-MM-yyyy HH:mm:ss"):StatusTransitions[n].Created}
   ${StatusTransitions[n].OldStatus}
   ${StatusTransitions[n].NewStatus}
#{end}
 
or
 
#{for <VariableName>=StatusTransitionsCount}
   Content and StatusTransitions Mappings. Example: ${StatusTransitions[VariableName].Field}
#{end}

Note that, if you use both maxWidth and width mappings, only the max value will be read. The same behavior happens with height and maxHeight.

#{for attachments}
   ${Attachments[n].ID}
   ${Attachments[n].Name}
   ${Attachments[n].Author}
   ${Attachments[n].AuthorFullName}
   ${dateformat("dd-MM-yyyy HH:mm:ss"):Attachments[n].Created}
   ${Attachments[n].Size}
   ${Attachments[n].HumanReadableSize}
   ${Attachments[n].MimeType}
#{end}
 
or
 
#{for <VariableName>=AttachmentsCount}
   Content and Issue Mappings. Example: ${Attachments[VariableName].Field}
#{end}

#{for labels}
   ${Labels[n].Name}
#{end}
 
or
 
#{for <VariableName>=LabelsCount}
  ${Labels[VariableName].Name}
#{end}

#{for projectVersions}
   ${ProjectVersions[n].Name}
   ${ProjectVersions[n].Description}
   ${dateformat("dd-MM-yyyy"):ProjectVersions[n].Start date}
   ${dateformat("dd-MM-yyyy"):ProjectVersions[n].Release date}
#{end}
 
or
 
#{for <VariableName>=ProjectVersionsCount}
   ${ProjectVersions[VariableName].Name}
   ${ProjectVersions[VariableName].Description}
   ${dateformat("dd-MM-yyyy"):ProjectVersions[VariableName].Start date}
   ${dateformat("dd-MM-yyyy"):ProjectVersions[VariableName].Release date}
#{end}

a simple example iterating the details of issues from a specified Project:
 
#{for i=JQLIssuesCount|clause=project = DEMO}
   ${JQLIssues[i].Key}
   ${JQLIssues[i].Summary} 
#{end}

or a more advanced example iterating the details of issues linked with the current Issue:
 
#{for m=JQLIssuesCount|clause=issuekey in linkedIssues (${Links[j].Key})}
   Linked Issue ${JQLIssues[m].Summary} has ${JQLIssues[m].LinksCount} links
#{end} 
 
or an also advanced example iterating the details of the Parent issue from the current Subtask:
 
#{for i=JQLIssuesCount|clause=issuekey = ${ParentIssueKey}}
	${JQLIssues[i].Key}
	${JQLIssues[i].Id}
	${JQLIssues[i].Description}
#{end}

You can also use a Filter Name or a Filter Id as a clause. For more info, read this.