*UPDATE* Sketch version 44.1 fixes this issue, pretty much negating the need for this plugin:
— Sketch Hunt (@SketchHunt) May 22, 2017
To the surprise and dismay of many, Sketch 44 removed the previously available ‘feature’ that allowed users to place a large artboard behind multiple other artboards and export a composite image of the entire set.
— Sketch Hunt (@SketchHunt) May 17, 2017
— Sketch (@sketchapp) May 17, 2017
I hope they do restore this feature. In the meantime, David Williames was kind enough to create a plugin that replicates the behavior of this deprecated feature.
“Export all selected artboards — even when there are artboards overlapping each other, with a single action.
This mimics the behaviour that occurred before Sketch 44. It does this by creating a temporarily slice around each artboard, and copies the same export options from the artboard being sliced.”