With 6 buttons, the Elgato Stream Deck Mini gives you complete control over your livestream. You can set each button's function yourself. For example, you can easily switch between the various scenes in OBS during gameplay. You can also assign files to a button, to easily play the perfect GIF file during your stream. The buttons themselves are small screens, so you can place images on the buttons to quickly recognize them.
Tip: on its website, Elgato has a useful key creator to quickly make nice icons for your buttons.