Kodi, formerly known as XBMC, is an open-source media player that is available on a variety of platforms - including Android. If you use Kodi on your Android TV, you'll be happy to know that the next major release will support Leanback suggestions and voice search.
This means that Kodi will fill the home screen of Android TV with content suggestions from your library, much like YouTube and Google Play Movies. And as you can probably guess, the voice search functionality means you can ask to play anything in your Kodi library from Android TV's Google search (it will not return results from add-ons). Take a look at the video below for a demonstration:
These new features will ship in the upcoming Kodi 18 release, but if you're impatient, you can try it out now with a nightly build from Kodi's website. You'll have to enable 'Allow remote control via HTTP' for these new abilities to work, which can be done by opening Kodi's settings and navigating to Services > Control. If you encounter issues, it is recommended to leave bug reports at the official forum.