What are the best open source software training programs/courses?

As of my last knowledge update in January 2022, there are many open-source software training programs and courses available. However, keep in mind that the availability and popularity of specific courses may change over time. Here are some notable options that were well-regarded as of my last update:

edX:

edX offers a variety of courses from top universities and institutions. While not all courses are open source, many cover open-source technologies and tools.