I've participated in a few as well over the last few years
Mostly through Coursera. I highly recommend the 9-11 courses by Duke University's David Schanzer. I learned a lot from those.
https://www.coursera.org/course/respondingto911
Also Public Speaking from University of Washington
https://www.coursera.org/learn/public-speaking
last of all the following should be a required course for everyone IMO: Psychological First Aid from John Hopkins
https://www.coursera.org/course/psychfirstaid
never spent money on any of them. I have just used them for my own education and betterment.