Finding new Google search features is a hobby for many in our industry. Being able to see them, try them and report on them before others see them can sometimes offer SEOs and webmasters a competitive advantage. Also, sometimes it can be a waste of their time. But at least you get in the mindset of what Google is thinking about testing.
Google is promoting via a Google Now card to some Android users a beta channel for the Google Search App for Android. Going their on your Android device will let you opt in to become a beta tester and let you download the beta version of their Google Search App.
Here is a picture of that:
The Google Now card promises experimental features that let you see and test some of the search features, Google Now cards, predictive search, etc before they are released to the main Google Search App.
I'd recommend you give it a try, if you have an Android device or spare Android device.
Forum discussion at Reddit.