Champions League/Arena Rotation

The Champion's League contains 3 different arenas to run in, each one containing a special rule that changes how points can be earned by a small degree. Each arena only has a certain amount of playable cookies, pets, and treasures that can be run with. After each season, one of the arenas are cycled out and replaced by a new one, in sequential order; Arena 1 gets cycled out first, then Arena 2 in the following season, then Arena 3, and then back to Arena 1. This page documents all the arenas that have been available per season, alongside the buffs and combis that could be used.

List of arenas available in each season
Please note that unless otherwise stated, and $π$ can be run with in every arena, in every season.