Ninja Gaiden 3: Razor's Edge at the moment. Despite the Wii U's commercial struggles, studio head Yosuke Hayashi told Joystiq his team would consider games for the Nintendo system, as long as they're a good fit.
"Of course, I think there are games that would be good for Wii U," Hayashi told us at Gamescom. "So I think we need to still see what exactly those games they are and how you make a game for Wii U that is perfect for the Wii U. So if we get a chance to make a game like that, well, maybe we can think about it then. But right now we have no plans to port existing games to Wii U."
Razor's Edge was one of the first third-party games announced for the Wii U, and the port brought welcome revisions to the PS3 and Xbox 360 original. As for Team Ninja, it's currently collaborating with Keiji Inafune's Comcept and Lost Planet 3 dev Spark Unlimited on the zombie-plagued Yaiba: Ninja Gaiden Z, due on Xbox 360 and PS3 in early 2014.