A very beginner friendly introduction to learning the Pistonball environment using SuperSuit and Stable Baselines 3
https://nbviewer.jupyter.org/github/gsverhoeven/gt_rl_course/blob/master/week_8/marl_tictactoe.ipynb
An example-based introduction to the PettingZoo API for beginners, that then shows users how to use tabular Q Learning for self play in the Tic Tac Toe environment.
A tutorial on learning PettingZoo multi-agent environments with the RLlib reinforcement learning library, intended for those generally new to RLlib but with nontrivial experimence in reinforcement learning