Best Science & Engineering courses
The 7 Science & Engineering courses Redditors recommend to each other on Reddit, ranked by how many people recommended each one, how strongly, in how many separate threads and over how many years (20 recommendations). 5 of them are free. How ranking works.

6.002 Circuits and Electronics
MIT OpenCourseWare · beginner · free
Commenters call the lecture videos very good and describe them as a godsend for learning circuit basics, with one pointing to the MITx version as super interactive.
Google IT Support Professional Certificate
Coursera · beginner · freemium
Commenters call it a good way to understand how computers work and say it helps on a resume, even for people already working in IT.
AWS Certified Solutions Architect course
Adrian Cantrill · beginner · paid
Commenters say Adrian Cantrill's courses are in-depth and easy to understand.
Technical Writing Course
Google Developers · beginner · free
Commenters call it a quick, solid starting point for better technical communication, with one saying it was "quite good" and another highly recommending it.
CS253 Web Security
Stanford University · intermediate · free
Commenters point to it as a free Stanford web security course, recommended in threads about server security and computer science learning resources.
The Quantum Computational Universe (Patrick Hayden)
YouTube · intermediate · free
One commenter recommends it as an accessible route into quantum information ideas behind black hole research, pointing to specific introductory and follow-up lectures.

Circuits and Electronics 2: Amplification and Active Circuits
edX · intermediate · free
Commenters point to it as part of the MIT sequence on edX for learning electronics on your own, noting it is taught by the edX CEO and is the flagship course.