Want to reboot your Raspberry Pi? Don't even worry about opening a terminal window—the HomeBerry Android app, developed by Andrej Martinák, has everything you need to control your Pi remotely with a few basic functions.
HomeBerry works with a custom REST API. This API must be installed on your Raspberry Pi in order for a companion Android app to communicate the Raspberry Pi. You can read more about and download the HomeBerry API repository on Github. Once it's installed, you'll need to load the HomeBerry app onto an Android device (an Android tablet should work just as well as a smartphone).
The Android app features a user interface with plenty of options and settings. You can restart your Pi, enable and disable Bluetooth or even launch specific apps like Kodi.
If you want to take HomeBerry for a spin, you can check it out on Github. Martinák provides all of the source code and plenty of info to get you started. This isn't his first project, either. Be sure to follow him on Reddit for more projects and future updates to HomeBerry.