Honestly I wouldn't mind a good ol' fashioned global group chat. I know there are moderation issues there, but I miss IRC and want more of that feeling elsewhere.
Actually, that's a good point - why is there no HN IRC?
There is a #hackernews on Libera.chat, and I believe I've seen a #ycombinator (or something similar) somewhere. No idea how official they are. But every HN-based community I've seen was a ghost town outside HN itself.