Punch-Out, Balloon Fight, Wave Race, Space Firebird. Too many to name.
I feel like "sitting on games" is a bit of an unfair complaint when the company in question has been consistently making games longer than anyone else in the business, amounting to 50 years of production. Like... yeah, they sat on Punch-Put and Balloon Fight and Wave Race, but seriously? They release a minimum of six or seven games per-year on the first party ticket and have dozens of franchises under their corporate umbrella.
Are we really going to cry foul that Balloon Fight didn't get an entry in the last 30 years? Maybe they could come up with something creative and someday they probably will, but really? Who is knocking down the doors for Wave Race? And I like that series, but I am also not sitting around crying about 1080 Snowboarding getting a pass for all these years. Punch-Out is probably floating up near the top of games that could and should get another entry soon, it is a simple formula that is awesome and fun.
Meanwhile there are serious demands for more Mario, more Zelda, more Animal Crossing, more Mario Kart, more Smash Bros. and a slow-burn on stuff like Metroid and Donkey Kong and Kirby and F-Zero and Splatoon and Star Fox. Those are immediately higher priority than the other niche games mentioned, however good they may be.
And surely there are too many to name, Nintendo has more first party games than just about anyone. But they don't have unlimited development capacity and it is a feat that most of what they do make comes out at such a reliably-high level of quality as often as it does. I'll complain myself about a lack of an ARMS sequel but I don't lose sleep over it. Maybe I get it someday, but maybe I don't. In the meantime I'm happy to have a really great Donkey Kong game and a fantastic Mario Kart game. Plus Metroid is probably going to be excellent.
It seems like an excuse to complain rather than a bona fide gripe with the developer. Give me a sequel to Joy Mech Fight or don't, I'll deal.