GridWichterle for Android
GridWichterle is an Android app that displays a grid overlay over whole system which is very useful in verifying app design. The grid help designers adhere to Android Design Guidelines – Metrics and Grids and in making the app look aesthetically pleasing. The tool is also very easy to use, just run the app and grid will appear over the whole system. The grid can be removed via notification. You can also configure various parameters such as the grid size in dp, grid color and transparency and full-screen mode.