iOS Pick: FaceApp
Megan Morrone's app cap on iOS Today 331 is FaceApp. First you take a photo of yourself not smiling. The app then uses neural networks to change your face in various ways. It can make you look like you're actually smiling, show you what you look like as the opposite gender, and make you look young, old, and "hot."
This app is fun, but it is admittedly limited in its scope. It also has some potential social problems, as its changes (or lack of changes) can be insulting. It also could be used maliciously, like to make someone look like they're smiling at a somber event, for example.