Overall, Senior Planet from AARP has some great resources. They even run support groups for victims of fraud. https://seniorplanet.org/on-demand/

Generations is pretty good if not a little dated but all free. http://www.generationsonline.com/

Drive your learning is great collaboration between AT&T and Digitunity. I'm uncertain if every course is free but I'm really loving their cybersecurity lessons. http://www.driveyourlearning.org/

Oasis has some great videos as well. Again, I appreciate their safety lessons. https://connections.oasisnet.org/Safety/