Ask HN: How do you troubleshoot desktop Linux crashes/freezes?

I've been using Linux all my life. I’d like to be able to claim that it’s stable, but that’s not my experience :) So I’d like to get better at recovering from freezes and crashes, and finding the root cause.

I make extensive use of Ctrl+Alt+f3, and magic system request keys (Ctrl+Alt+PrtSc+f; Ctrl+Alt+PrtSc+reisub). But often the system is too far gone to drop to a virtual terminal. In these cases, I usually try to find clues in dmesg/syslog/journalctl.

The bulk of issues seem to be caused by Nvidia GPUs, and suspend.

What are your go-to commands for recovery? And, when that isn't an option, how do you post-mortem after rebooting?