Ask HN: What CS knowledge would be beneficial to a self-taught programmer?

I am a self-taught programmer, proficient in Javascript, Node.JS, PHP and Python. I never got a CS degree but have spent over the 4years programming for small startups. Currently I am 23 years old. What skills would be nice to have? I have been reading up on Algorithms, but I would like people who have gone down this path to share what tools and tutorials they used and probably a study curriculum they used. Thanks in advance