Here is another plank board that lets you use your smartphone as you exercise. The Yes4All Inno Board can not only be used for planks but also squats and lunges in standing mode. You can also remove the handles to use this board as a twister.
This board has a wood construction and can handle up to 350lbs of load. It can be used with plenty of balance games in the App Store, including Mega Jump, Cube Runner, and Doodle Jump.