This is a living list, gathering links suggested by the community. Please share your recommendations in the comments section or Discord, I'll update this post accordingly. Thanks!
- What Every Programmer Needs To Know About Game Networking
- Making a Multiplayer FPS in C++: Series of articles about designing the networking for multiplayer games. The examples are in C++ but the solutions can be adapted to other languages.
Article: Choosing the right netcode for your game (compares MLAPI, DarkRift 2, Photon PUN, Photon Quantum 2.0 & Mirror)