Retail
+1 Bayonetta
+1 Bayonetta 2
+1 Hyrule Warriors
+1 LEGO City Undercover
+1 Rayman Legends
+1 Resident Evil: Relevations
+1 Super Smash Bros.
+1 Tekken Tag Tournament 2
+1 The Wonderful 101
+1 Wii Fit U (sports / fitness) - this game is not for everyone but if you want to have a physical jerks in a more or less fun form give it a try. It's also pretty addictive to compete with your family members using a FitMeter gadgets.
eShop
+1 Bit.Trip Runner 2
+1 MK8 DLC Pack 1
+1 NES Remix
+1 NES Remix 2
+1 Toki Tori 2
+1 Unepic
+1 Art of Balance (puzzle) - solid remake of the great Wii puzzle title, better graphics, new modes, local multiplayer. It's all worth to try, there is a demo as well.
+1 Cloudberry Kingdom (platformer) - hardcore platforming for a genre fans. Must have if you like when a game kicks your ass.
+1 Color Zen (puzzle) - very relaxive brainteaser title, simple idea & great embodiment, give it a try if you're a puzzle addicted person. There is also a Color Zen Kids game which may be considered as a level pack. Both are pretty cheap.
+1 Knytt Underground (metroidvania / platform / puzzle) - this game is a piece of art and may be a deep & long adventure full of a discoveries if you'll give it a chance.
+1 SteamWorld Dig (action / platfomer) - it's all about digging your heritage mine, very deep & enjoyment game.
+1 Wii Sports Club: Golf (sports) - a definite golf game on platform & ever, intuitive & innovative controls using both a Wii U Pad & Wii Remote Plus would not make you indifferent. Local & internet multiplayer adds a lot of fun. The best title in the Wii Sports Club series. You may also try Bowling & Baseball counterparts but me was not too addicted in its gameplay.