A lot of the work I do is made available to everyone for free, I tend to be service driven not profit driven. This began in the 1990s with provision of a variety of weightlifting training and competition resources. Then in the early 2000s, I created a free online anatomy textbook for my university students to save them the massive cost of mainstream publisher textbooks. I followed on by making all of my Strength and Fitness standards available. Those early standards were, and still are, used as the basis for many apps and websites. The Strength Standards linked below are completely revised for 2023 (all previous iterations are now moot).
Here are some links to free book resources, some by famous people (anatomist Henry Gray), some open access, and a couple chapters from my books.