Forest is a highly rated productivity app that gamifies focus. When you want to work, you plant a virtual tree; if you leave the app to check your phone before the timer ends, your tree dies. Over time, you build a "forest" that visually tracks your focus habits.
“I've used it for over two years now, and it's amazing... But recently, it has begun to sap a LOT of battery.” Apple
“The only thing I would fix is that only Plus members are allowed to see more detailed stats. Personally I think that we should see our stats.” Apple