XD has prototyping, Invision Studio will have prototyping so I thought I would add it to Sketch. You can see it in action here.
So what does the Sketch plugin do?
Have overlays appear and disappear by moving layers around and animating the transitions.
Quickly wire up your artboards to see how the flow of the application works. Preview the prototype in Sketch or on a smartphone.
The prototype makes use of Sketch's resizing constraints and responsive artboard groups so that it can adapt to any screen size.
You can sign-up for early access at protowire.com.