Cells at Work! is a comical, fun, and educational anime focusing on the immune system. All the human body cells are enthropomorphized. If you like this anime, I recommend you to watch Dr. Stone, which is the most obvious choice since it is also an anime related to science. Heaven's Design Team (Tenchi Souzou Design-bu) is also a good choice. You can learn many unusual facts about animals. After watching this anime, rabbits will be a lot less cute to you.