One Handed iPhone Keyboard
With iOS 11, you get to use the iPhone one-handed keyboard without installing a third-party keyboard. This is amazing if you have smaller hands but love larger screen phones.
With Apple's continued push towards bigger screens, this is also an amazing iOS 11 feature that you will like with the iPhone 8 this fall, since it will likely have a bigger screen.
Go to Settings -> General -> Keyboard and then choose which hand you want the keyboard to be set up for. You can also hold the globe or emoji on your keyboard and choose left or right handed.