Create a button that does (almost) anything you want with Do Button.

Do Button allows you customize your own smartphone button. You can program it to turn your Philips Hue lights on and off, set your Nest thermostat to a certain temperature, track your next journey in Google Drive, or send an email to your partner that you're on your way home. You can also easily access the button from your iPhone's lock screen with the handy widget.

Price: Free (iOS)