Most of the courses over at The Sweet Setup are based off of a specific app, but a couple of them are app agnostic. Examples of this include their Time Management, Calm Inbox, and Simple Habits courses. They’re all well designed and usually fairly well priced.
I’ve also really enjoyed Ali Abdaal’s courses on Skillshare. SkillShare is a monthly fee, but you can usually find a YouTuber being sponsored by SkillShare and get a free 30 day trial.
As a bit of semi-self promo I work for Signum University (well volunteer) and we’re starting to offer soft-skill courses as a complement to our MA program. I’m not directly involved with these courses, so I hope mentioning them is ok. While most aren’t geared at productivity the “Time Management” course might be of interest. https://path.signumuniversity.org/badges/ Unlike the courses I’ve mentioned so far, these are live classes taught via webinar software and run as small groups.
Finally, completely outside of the range of reasonable priced courses there’s Tiago Forte’s Building a Second Brain. I paid $1500.00 for the course and would definitely say it’s worth it, for certain individuals. I have lots going on and am really passionate about note taking. While the course was expensive - I did get a couple of nuggets from it which have more than paid off for me.
I’ve found that most productivity-oriented courses don’t offer much in the way of revolutionary new concepts. Instead they’re good refreshers of things I already know or a way to help me view something from a different angle. They’re much more expensive, but I’ve found the live cohort-based courses to be much more valuable because of the group accountability.