So you would like to do more with your smartphone camera? The Helium Core Smartphone Rig has you covered. It allows you to attach lights, microphones, and other gear to your smartphone to produce higher quality work. It has mounting 1/4″-20 mounting points on all 4 sides.
The Helium Core chassis has 17 mounting points (iPhone 6 Plus version). It is made of aircraft-grade aluminum. You can also use lenses to do more with your iPhone camera. Costs under $170 at this time.