Calendar Sync for JIRA connects your JIRA items to your desktop or mobile calendar. Specify as many calendar “feeds” as you like; each one can be configured with a JQL query and rules for how the items are translated to calendar entries.
Add-ons by Expium LLC
Supplementing the built in bulk update features, this add-on lets you perform mass deletion of an unlimited number of issues. You might not need it very often, but when you need it, you really need it.
Query Feed for JIRA makes it easy to expose the output of any JQL query for consumption by external software, most typically your own software that needs to integrate with JIRA data. Full configuration settings including security. Pull or Push.
Visualizer displays each of your issues as a card on a zooming, scrolling canvas. You can then choose how these cards (issues) will be organized visually, choosing projects, issue types, sprints, assignees, or any other JIRA field to group them.