Participate in medical studies. If just the thought of this frightens you, know that the intensity of such studies varies greatly. Some studies ask participants (particularly those with medical conditions) to test treatments or medications that can have adverse side effects, but others ask participants to perform physical tasks with no lasting effects. If you are able-bodied and paranoid about keeping it that way, you can even participate as a control in a study at a nearby medical research facility or medical school.
How much will you make? I think my best month with Google AdSense was almost $5,000 over the last ten years. That amazing month blew my mind since it was actually near the beginning of my blogging journey. When you go from making zero to $5,000 in a month, that will rock your world. For me, it also got me even more excited because I knew there were other ways to monetize.