Ask HN: What are the best learning references that have you found?

I'm looking for introductory stuff like the following: - https://howhttps.works/ - https://howdns.works/ - https://tls13.xargs.org/ - https://beej.us/guide/bgnet/ - Eli the computer guy series on youtube (A+, Networking, Cloud Computing) Reason for asking: i like sharing things like this to people new to programming / development in general.