There are lots of things that has not been discovered so I'm sure there are apps that has not been made.

Have you ever come across any app that tells you the mind of another person? Apps that can reveal the hidden secret about your spouse? What about an app that tells you food or drink is poisoned? Maybe by scanning the drink or food with the app through your device a red light will blink to show that there is poison in what you are about to take.

A lot of apps have not been created and I believe research is still going on and many apps will show as time goes on.