This Google Sheet curates all Udemy courses that are currently available for free. The sheet is updated every few hours, and it internally uses the Udemy API with Google Scripts to scan the Udemy database for free courses in the dev category.

https://www.labnol.org/tech-courses-200403

Somewhat tangential: I have yet to find a useful Udemy course. Every time I find one on a topic that interests me, it turns out to be more superficial than the project's own readme file, or is riddled with misinformation, omitting important details, or simply filled with irrelevant useless information and activities.

My "favorite" kind is the "advanced course on xxx", that is intended for seasoned veterans of the topic, and 60% of the course is downloading and installing the tool along with an in-depth explanation of a "hello world" equivalent exercise.

I know, it is a rant. But I got excited so many times, just to be let down again and again...