I am very happy with the Caudabe Veil XT on my matte black iP7. Perfect fit, super thin and it works well with my 3D screen protector.
Yeah, if you need an ultra thin you can't go wrong with Caudabe. Awesome quality and customer service. https://www.caudabe.com/products/the-veil-xt-iphone-7?variant=22644334916
Had one for years and get one for every new iPhone. The iPhone 7 iteration is definitely improved over the previous ones with much better grip. I'm still waiting on them to release the Sheath as that's the best combination of thinness and protection IMO. Using the Veil XT in the meantime.