All that was unannounce that we knew about was Pikmin.

I'm going with something new.

Metroid

The only one I'm sure of is the next 3D Mario, and whatever Retro Studios are developing. We can assume, of course, given the increasing scarcity of major Nintendo releases in the last two years, and the fact that so few of those came from EAD/EPD, that much of Nintendo's resources were pushed away from NX and onto Switch.

In an Edge interview around the time Super Mario 3D World launched, Yoshiaki Koizumi confirmed that development had already begun on the next 3D Mario title. Presumably at some point (early) in 2015 development was shifted to Switch. Similarly, after work finished on Tropical Freeze in late 2013, Retro Studios began development on their next project. Again, I'd assume that shifted onto Switch in 2015.

It's dangerous to even begin speculating on what else there is. Regardless of what Nintendo announce in January, I fully expect there will be disappointed fans because Luigi's Mansion 3 or Kid Icarus or F Zero or Metroid or franchise x aren't announced for Switch. Personally the one franchise I'm not expecting yet is Metroid, though I'd like to be wrong.

Hello Kitty Kruisers 2.

A dark and grimm game where Hello Kitty enlists in the Navy and has to fight terrible naval battles on a World War III setting. GOTY 2017.

Without question the 3DMario game and Retro's next title. Although from the outset with the 3D Mario Yoshiaki Koizumi said that he wasn't sure if it would be on Wii U or the next system, and that was 3 years ago. By then Nintendo knew the system was flopping hard and titles that were envisioned for Wii U were quickly being shifted. They've worked on Switch for 3 years as well, so you could say they moved or started out for switch. Either way, if Wii U was more successful they probably would have been on that system. There are probably another title or two that went through a similar process.

Hopefully Bayonetta 3.

The 3D Mario game
Pikmin 4
Retro
Next Levels

..off the top of my head