Btw, serial console also allows login even if networking is down (I mention this because if you have Wi-Fi it is often not enabled until after the GUI login). There is also the local console login; if you use CTRL+ALT+F2 through CTRL+ALT+F6 from a GUI, then it goes to the other login session, and those do not use the GUI. If you are not in a GUI, just skip the CTRL and use ALT+F1 through ALT+F6 (ALT+F1 would take you back to the GUI).
ssh is best because it allows you to copy the log file via scp. Serial console is close because it can log a session, and you can just “cat” the log file.