Question types: Drag and drop onto image
As of Moodle 3.0, this question type is part of the standard Moodle release. That is why there is no plugin from Moodle 3.x. You don't need one!
There are working examples in eAssessment with Moodle on our OpenLearn site.
The documentation is in How to create questions in Moodle on that site.
Demonstration of this question type courtesy of Dot Garman.