The iPhone 7 Plus retail box contains the standard accessories - a wall plug, a Lightning cable, and Apple’s EarPods ending on a Lighting connector. The supplied charger is 5V/1A which is a pity as the phone is capable of charging twice as fast with a third-party 5V/2A charger.
For the first time in an iPhone there is a fourth thingy in the box - a Lighting-to-3.5mm analog adapter. Using one is not as convenient, it was a mandatory addition so the users can use headphones of their choice.