Occasionally, I wander into to stack exchange outside the programming and get blown away by the stuff there is. For instance, could you imagine anyone going to these lengths to answer a question about React hooks etymology - Which came first? Chinese 蘑菇 or Mongolian мөөг? - Chinese Language Stack Exchange, and then tone your own answer down with “But those are just general articles, not scholarly credible.”

Another one of my favourites is the Worldbuilding Stack Exchange for people creating worlds for games and fiction.