From Wii U I think the essentials are good (MK8, SM3DW, SMM, TLOZ BOTW)
But, some game I never seen someone talk about is FAST RACING NEO, I love that game and is such a nice racing game with high detail graphics and performance for a underpowered console like the Wii U.
Meanwhile for Wii, excepting the essentials (MKWII, NSMBW, SSBB), I think Super Paper Mario is kinda underrated in this days, a lot of people still think its bad because its the only game in the franchise that is not full rpg, but I actually think its the last Paper Mario game that was good before Nintendo started doing weird things with the franchise.