Xenoblade easy. I love The Last Story and feel it's very underrated but it's only a published game.. Chibi Robo and Captain Rainbow and other obscure but interesting IPs were just that. Interesting. Xenoblade is one of the best IPs the last decade period and easily Nintendo's best in terms of quality. Splatoon is neat in that is has the Jet Set Radio vibe and it's fun for a while but I never play it that long. ARMS is a decent Virtual On clone. Xenoblade is so rich tho. Storytelling. Worlds to explore. Characters. Worldbuilding and amazing music. When it comes to publishing The Wonderful 101 and Astral Chain are some of my fave games released on any platform in the last 10 years.

Out of the games on the Poll Splatoon has my most played hours. 300+ on Wii U and 1000+ on Switch.

There are countless great ones, but I have to go with Xenoblade. Such a phenomenal franchise. I've said this in another thread, but this series deserves Final Fantasy level sales.

Everytime I describe splatoon as a shooter game I have to think twice because my favourite weapon type is the umbrella lol.

I was going to pick Ring Fit Adventure but Wii Sports is just too good.

I think somehow i enjoyed Metroid Prime 2 much and then Splatoon 2, just a weird thought in my mind. Because i loved playing the local multiplayer mode with my friends irl as much as Half-Life Deathmatch i used to play LAN party a lot.

Style Savvy

Is such a feel good series and incredibly addictive, the gameplay loop of matching up styles, discovering new fashion items the more you progress and helping out all these character through the game, with a handful of them having a decent character arc that makes it feel like there is a sense of progression, plus all the activities you can do make this one of my favorite current Nintendo series. Is a fashion game with a ton of effort, depth and meaningful things to do.

I also love that every entry manages to be better than the last one.

Animal Crossing is just phenomenal

Also love Splatoon. Playing only both in the last weeks

I feel like none of these IPs are as stellar as Mario, Zelda or Metroid. It's something I think Nintendo has been lacking these last two decades, an IP that can rival Nintendo's own biggest productions and the biggest AAA titles of each year. Something in particular they're missing is an action-adventure game different than Zelda.

I voted Animal Crossing. My personal favourite from the options.
Honorable mention:- Wii series.
It has been pointed out in this thread that Chibi Robo qualifies for this list. As i have just realised , it indeed does. So with thought my actual vote would be very close. Not sure if i could pick between Animal Crossing and "Other" (ie Chibi Robo)