>>42255753Not him, but I have a "proper" main team, as in a group of six that I consider my personal team as a Pokemon trainer, with a signature/ace who has been with me since my first playthrough of Emerald (pic related).
I bring them to the latest game once I beat the league with my story team. I do post-game with them, and post-game battle facilities. Sometimes I swap them out for new things or try old ones again, sometimes one is there for years or months before I try something else, but my ace has never changed.
I have sentimental attachment to my them, especially pic related. I enjoy being with them, battling with them, trying to make fun strategies with them, beat side-content (Contests/Battle Royals) and post-game facilities with them etc. I also use other Pokemon if I want, but being with my main team is just how I play post-game.