I agree with the other answers that empathy, curiosity, discipline and so on are important... but those are more attributes and qualities than skills per se. So if you were seeking a more literal answer:
The web trinity is a bit of a gimme. If you don't know those three, don't call yourself a web developer. If you don't know the native, vanilla tech; all your abstractions will be learned on shaky foundations. If you don't know how to write HTML, you will write bad CSS and JS because your DOM is crap.
Bash unlocks so many things. It's the de facto standard working environment for web tooling; and it's a massive boost to learning things like devops, where you are often automating tasks you'd otherwise run manually on the command line.
Public speaking doesn't just mean getting up at a conference. It's also the ability to talk clearly to the room in a big meeting, present your ideas to your leadership team, pitch to customers and so on.