Group package tickets offer a discount on admission for larger groups. For example, you could offer them to groups of five or more attendees. These are useful for conferences or other larger expensive events, where the cost of admission is high (and needs to be). Incentivize higher attendance with group sales. B2B conferences especially benefit from marketing to whole teams rather than individuals within an organization.
For their upcoming conference, Business Insider offered two different group package ticketing options, giving the second one an even higher discount.