Sometimes you need to change your phone's settings in a hurry. Enter Extended Controls. The app gives you a lock-screen-friendly widget that can hold whatever one-touch toggles you want. You could set it to have a whole lineup of toggles for things like Bluetooth, Wi-Fi, airplane mode and volume -- or just create a single-function button for one frequently used command.
Extended Controls even has the ability to turn your phone into a Wi-Fi hotspot -- with or without an official carrier-authorized plan, in some cases -- which can prove to be quite convenient as a lock screen option.