So cars are pretty bad when it comes to toxic fluids, especially older ones that leak a lot. Recently I decided to try some easy things that make my car slightly better. One of the easiest is purchasing radiator fluid that is less toxic. Biofrost, Sierra, and Prestone all make safer alternatives to traditional antifreeze. If you google it you will find more, most are easier to order online than found in store in my experience. At the moment I have only used the Sierra brand and I have not noticed any difference compared to the more toxic versions.
The second easy thing is wiper fluid alternatives. There are brands that sell eco-friendly wiper fluid, or you can make your own. I have tried making my own and I think it is the best solution. It is cheaper and super easy. There are some excellent recipes online that work well, below is where I got my start on my wiper fluid. In the summer just water and a plant based window cleaner works great for me, and currently I just reuse my old fluid bottle. In the winter however I mixed mine with traditional because it would freeze often while driving in the mountains.
It is only a small start to making a car more eco, but it is better than nothing. Small steps are better than no steps.