Seriously EVERY Wii U owner should have Super Mario 3D World. And if you still like 2D Mario, New Super Mario Bros. U is severely underrated. It kicks the ever loving crap out of NSMB2; quite a curse that they came out in the same year.
I also stand by Woolly World, best Yoshi game since the original. And I still gotta get Xenoblade X sometime, it looks awesome but I never got the chance to try it.
Also, my favorite digital-only titles:
The Cave, Shantae and the Pirate's Curse, Nano Assault Neo, and Fast Racing Neo.
I'll definitely see if I can find any decent prices on those games, money being kinda iffy thought not sure when I'll be able to. Wonderful 101 I hear is a lot of fun.
Wonderful 101 is a great game but what bugs me about it is that they left menu keys on the Gamepad active while you're expected to be drawing on the thing. Somebody didn't think that one through and it leaves me using the right analogue stick more than my stylus, which is sad given that the Wii U was expressly built to encourage the opposite.
Also on DeviantArt, Rumble, DLive.tv, and the Fediverse (@freespeechextremist.com and @bae.st)