Star Fox Guard
It's finally a game that actually makes good use of the gamepad in it's core gameplay. Unlike Star Fox Zero, Star Fox Guard has incorporated the gamepad in a fantastic way and this game couldn't actually exist without having the gamepad.
It's kind of sad that it's taken Nintendo this long to make a game that justifies the Wii U gamepad, for every other game it either feels extremely forced or it just adds some nice-to-haves. In Star Fox Guard it's critical to the gameplay.
You use the gamepad to position and select cameras in a tower defense style game. The TV screen shows you the individual views from all those cameras once the waves of enemies start and that's also where you aim and fire to defend.
If my thoughts about Star Fox Zero turned you off of that game yesterday I would highly suggest you grab Star Fox Guard standalone for $15 from the eShop. My kids and I are having an absolute blast with it!