I got serious about online courses about five years ago. I think gamification had a lot to do with it, too. Nice to get achievements for sections completed. Fun to see accomplishments and goals stack up, summarizing what was learned and when.
I'm always studying.
If I were to recommend these, in order, they would go:
Treehouse has always been my favorite:
However, Udemy is wonderful and the least expensive of the three. They always have $10 sales. Always. Last one just ended? Wait a week... tada! 20-40 hour courses for $10. You can also take courses, on-the-go, via the app for iOS or Android.
My three current courses on Udemy are:
Just started with Pluralsight last year. I like it so far. Lot's of deep dives. It's like a subscription-based Udemy with lots of really nice "self-testing/review/assessment" features. They also have apps for all platforms, including Amazon's Firestick. It's the most expensive of the three, but with tons of courses for the widest range of topics I've seen in a while.