We definitely know about H2O2 and have it on hand for fungal infections. It does work and its highly beneficial to your plants, since it promotes oxygen in the soil. Some growers will use it, even if they don’t have fungal/algae issues. I would also say that high humidity (and too much water in the soil) can contribute to mold/algae, so sometimes the solution is to decrease humidity as well. So, you can pull a couple of levers to deal with fungal/mold/algae growth and sometimes one or the other is a better approach.