Courses on EdX/Coursera are already fairly well indexed. There is a lot on OCW as well, but much of it is outdated, and often materials come without answer models making it hard to check your understanding. The below courses are (1) high quality, (2) publicly available, (3) have automated tests / answer models for the majority of materials allowing you to check yourself.

Programming Parallel Computers (U of Helsinki): https://ppc-exercises.cs.aalto.fi/courses

Operating Systems Engineering (MIT): https://pdos.csail.mit.edu/6.1810/2024/schedule.html

Distributed Systems (MIT): https://pdos.csail.mit.edu/6.824/schedule.html

Database Systems (MIT): https://dsg.csail.mit.edu/6.5830/sched.php

I would love to extend this list with more great courses, any suggestions? (Bonus points for hands-on courses involving probabilistic ML, NUMA or LLVM!)