I'm not working at the moment (and fortunate enough I can continue that for quite a while) and decided I'd just like to do some learning. I have a CS degree from about 12 years back and have worked as a Fullstack dev for the last 10 years, but after looking at https://careers.google.com/how-we-hire/interview/ realise that I'm really not playing at the same level as a what a lot of others are. There are a lot of gaps in my CS knowledge, so I'm working on my knowledge and skills while learning and improving on coding in Go.

As an ENFP I can't just sit and learn one thing at once, so I tend to cycle (with no particular pattern) through the following:

Graph Algorithms
A combination of learning on edx.org, and also reading through Tim Roughgardens graph algorithms book. Both are quite technical and take me quite a long time to digest the info. Sometimes I digress to dig deeper into things like Big O notation and the mathematical reasoning behind things like why you can drop constants and lower order terms, but on the whole really enjoying the materials.
https://courses.edx.org/courses/course-v1:UCSanDiegoX+ALGS20...
https://www.amazon.com.au/Algorithms-Illuminated-Part-Graph-...

Operating Systems
Udacity's Intro to Operating Systems course (https://classroom.udacity.com/courses/ud923)
Have also downloaded but not yet started reading "Operating Systems Concepts - 10th edition" which you can get from https://www.os-book.com/
I've only just started going through these, but essentially I feel like it's an area I'm lacking in terms of my understanding. When people talk about things like the Linux Kernel - before I really had no real idea of what that actually meant, and I feel like even with a few hours doing the course I am starting to have a much better idea of how things are put together.

Coding interviews
I signed up to https://www.techseries.dev/ and have started going through the problems in CoderPro that came along with the expensive $500-$1000 course. The coderpro course is basically just them going through leetcode questions... they even show that that's what they're doing in some of the videos. The main course is OK, but a bit basic.
I also have "Grokking the System Design Interview" course and I find that really good for showing how others actually think about and step through system design questions. I'd highly recommend this https://www.educative.io/courses/grokking-the-system-design-....
I also have Cracking the Coding Interview - http://www.crackingthecodinginterview.com/ which I've been using from time to time as well. I highly recommend this book, I find her step by step approach really insightful, and the book covers a crazy amount of material (it's a big book - Gayle Laakmann Mcdowell is a friggin machine).

Go Programming
I've been learning Go and using it to code up coding challenges. For Learning Go I've got a hard copy of "The Go Programming Language" which is really good and thorough - https://www.amazon.com.au/Programming-Language-Addison-Wesle...

I also did a course on Udemy https://www.udemy.com/course/go-golang-programming-course which I highly recommend for getting up to speed quickly. I also started going through Todd Mcleod's Go Clinic on Lynda - that was really good, but I didn't want to pay a monthly subscription so put that on pause for now. The GoClinic course is here https://www.lynda.com/Go-tutorials/Code-Clinic-Go/439416-2.h...