An application called WiFi Password Recovery might assist you in locating the WiFi password you previously used. If you've previously connected to networks but have forgotten the password, it can be quite helpful.This application is totally free. It assists in displaying all saved WiFi passwords and very portable and user-friendly. You can use your Google account to store your whole wifi password securely in the cloud. Just a heads up, root is needed. This application needs root authorization. When you lose track of the wifi passwords for all previous networks you connected to, it will be helpful to be able to see all of the passwords kept on your smartphone.