I rebuild from HEAD using homebrew quite regularly and have maybe had a single crash in years using Helix, so I'm shocked to see Julia report she's had crashes. But because I run HEAD, I can tell you what's actually merged which might not be released yet:
> Code actions on save
There are command on save hooks which solve the problem for Go, but I could see this being not as applicable for other languages.
> Fuzzy search
Man, I'm pretty sure this shipped before telescope was particular stable or popular. Although, I don't recall if Helix originally used the ripgrep backend at first. They reworked it earlier this year and it was a massive improvement.
> Automatically updating buffers
+1 to this. I constantly suspend (ctrl+z) my editor and sometimes forget about it and could really use this prompt.
> File tree in browser
Space+e or Space+E opens a hierarchical file explorer on HEAD, but this is definitely relatively new