Top Ones and click to buy (more info below):

Mariokart is amazing. With the auto-steering, my kids loved the game as young as 4. 5 years later, we're still playing battles and races, and enjoying the new boards they keep releasing! You can all be on the same team too!

Luigi's Mansion 3 is an adorable 1 player puzzle game. We'd take turns playing, as it's just so fun to watch others play too. My 6 year old was able to catch many ghosts, so it's great for kids 6 and up. And it's not scary scary, it's more like cute scary.

Smash is a fun, non-violent fighting game that's easy for kids. You can all be on the same team too. 

You knew this one would make my list, as my son is named Link!  It's a fun Link game, with beautiful new graphics.  It doesn't take too long, and the challenges are the right complexity.  My family loved it.   I'm playing Breath of the Wild on my own on the train. 

Strikers is a super fun 4 on 4 soccer game.  It has all the fun feels of NBA Jam, with shoving.  Plus there's power ups like shells and you get to play as Mario characters.  Our family would all play on the same team, and it was a blast winning cups.  Our favorite game for like 3+ months :) 

Paper Mario is a one player RPG.  It's fun to play, with a sweet and fun story.  We enjoyed beating it together.  Bobomb... 

They made a Katamari for the Switch!!!  In this game, you roll a ball over other objects to make it larger.  Super fun 1 player game.  We enjoyed this series so much it made it into our wedding vows, and this is a great version of it.  Earth really is full of things.

Mario Tennis on the switch is pretty fun.  Lots of characters, a challenging 1-player quest mode, and just the right level of silly fun.

Mario Party Superstars has some of the best minigames and boards from all the previous Mario Party games.  Part board game, part 15 second battles, all fun.  This is one of the greatest games ever made for fun with friends and family.

Tetris 99 is one of many fantastic games you get free with a Nintendo Switch online membership.  You also get Super Bomberman, Mariokart Boards, Pacman, SNES, NES, and N64 Games, and even some Genesis games.  I highly recommend getting the online membership.