Well, for that matter, I'd definitely go with my favorite games, but mainly Pikmin 2. It's a game I know so we'll that I feel it's somehow part of me. I genuinely have an extraordinary time every time I play it, doesn't matter which level is it, there's no bad part or section for me in this game.
In recent years, Xenoblade Chronicles X and Breath of the Wild also have filled this spot. It was always fun running around or flying in a Skell across Mira. And Breath of the Wild, while I didn't like it a lot initially, it eventually sucked me in with its relaxing gameplay. It's a game I can play after months without touching and immediately feel like everything is recognizable again and great. It's one of the very few Switch games I frequently replay.