So I have these six as my main team. The first four were the first important mons I added to my team from the places I went to (Starter, Goldenwood cave, Amethyst cave and Sheridan) while the last two are recent incorporations (Clefable being the main star in this V12 and saving my ass through sheer stalling in more than one plot battle)
Then I have a box in the PC with some of the mons I can rotate with, I try to maintain them in a minimum of utility mons, previous team members or mons I really like: