Not any new design pattern specially used for version 3.x of the Joomla CMS.
In Joomla, since its origin, several design patterns are used, notably MVC (Model-View-Controller), observers, factories and template method. O yeah, and singletons are still used too. In the Framework we also see dependency injection; plans are to also use that in the CMS. In Joomla CMS 3.4 the whole Joomla Framework is imported into the distribution.
Hope this answers your question.