As Google Assistant continues to grow in popularity we're seeing more devices launch with dedicated Assistant buttons. The LG G7 ThinQ was one of the first, but others have followed, and OnePlus even added the ability to the power button in the latest OxygenOS Open Beta 3 for the OnePlus 6. So clearly this is a trend we should see going forward.
Pressing these Assistant buttons or shortcuts does exactly what you would expect: it opens Google Assistant. What if you could make the shortcut do other things? Like open the notifications or switch to the previous app? That's exactly what you can do with Assistant Shortcuts by XDA member Stjinchan, and root is not required.
All you have to do is set the app as your default Assistant and then you can remap it to do other actions. You can see the full list of actions in the Play Store listing or in the XDA forum thread below.