I don't typically talk about my side projects, but I made a simple Montessori materials website for use while teachers/students have been stuck at home the past few months: https://montessori.tools

It has grown organically to 1,000 visits per day and ~$1,000/month. I have a couple of additional materials in the pipeline. Of course, I've already seen everything from the site shamelessly copied and posted elsewhere. That's fine; I never built it for the money (I built it for my wife, who is a teacher).