I would say the serverless model in general, is going to take off (it already is) really fast. Infrastructure as code, security as code. Big data, machine learning, neural networks/deep learning is taking off so without doing a PhD, at least high level awareness of the field is definitely worth learning, from Spark to Tensorflow, it's good to have familiarity with the field.

Understanding JWT and how it works as it seems to gain momentum.

Angular2, React, Vue I think are all worth learning and playing with as each developer will have a different taste. It looks like React is getting a lot of traction everywhere.

ES6, Promises, Async/Await, TypeScript, Babel, WebPack etc are definitely worth getting familiar with.