Unified Remote is a productivity app that can turn your mobile into a fully featured remote for your PC or laptop. The application has cross platform support by which you can control your Mac/Windows/Linux with your Android/IOS/Windows Phone.
I've used the Android version some times ago. I remember using it to control Kodi on an old laptop I set up as a media player and not only I controlled Kodi but I shut the laptop down, controlled the mouse and keyboard with no problems. I almost never had to open the laptop and use it's keyboard.
Huge amount of integrations to use as remotes. Has a lot of use cases.
The user interface could be slightly more modern.