We have shipped additional events in JIRA 7.5. You can now use them while building your plugins, or to get informed whenever an issue link is created or deleted. The new events are IssueLinkCreatedEvent and IssueLinkDeletedEvent.
When creating webhooks, you can use the following events. The string in parentheses is the name of the webhookEvent in the response.
This ticket remains open as issue linked or delinked events are still not part of a notification scheme. Right now, we do not have any plans for adding these events to notifications schemes. We will let you know as soon as the status of this suggestion changes.
Product Manager, JIRA Platform