- "How to write/build a [something]" if that "something" is fairly low-level, like a compiler.
- Just about anything involving bees.
- Highly-voted threads with mundane headlines -- i.e. either the content is good enough to not need a catchy headline, or its headline has been changed to be less clickbaity -- which might mean the mods thought it was worth saving rather than flagging into oblivion.
- Virtually any Show HNs that happen to make it to the front page
- Ask HNs that have > 50 comments.