Designing for Android TV is a lot different than designing for a phone. Users have a DPAD instead of full touch control. Additionally, many apps are recommended to use the standard Leanback library, which bundles common use widgets and code to simplify TV interface development.
When planning a TV app, it can help designers to develop mock interfaces and sketches to get a good idea of how the app will look. This can also be useful for developers so they have a clear goal of what the end result should look like.
Designer Qi Qu has posted a Sketch file on Dribble which is freely available for designers to mock up TV interfaces and share them. It’s a great tool for anyone who’s planning a TV app.