Honestly, this is the wrong question, but I understand the intent. What you really should be asking is "Where is the online community for your hobby/interest?"

The thing with HN, is it works for the startup/hacker/tech community, and that community has evolved here over time. If you want a link/topic sharing site for other interests, the answer is almost always going to be a subreddit.

But if what you really want is to be immersed in a community, those communities will be in weird corners that you have to discover. The reason for this is that a community almost always wants to be semi-private: discoverable by others that share the same interest, but just far enough out of the public eye to not get bombarded with bots/trolls/obnoxious people

Some examples I know of:

  - Voron (3d printer)? You want to be on their discord
  - BigGreenEgg (kamado smoker)? eggheadforum.com
  - MMA? sherdog
  - Electronics/Robotics diy style hacky projects? hackaday and go to the comment secion

The cool part about finding these true pockets of a community, is you can learn a ton about what truly makes them tick. What do they get excited about, what do they have an irrational hatred for, etc. If you've ever asked yourself "how do I market my app/website/saas", it's almost certainly because you haven't yet encountered where that niche community resides, and are falling back to more generic strategies. Find the community, and they'll tell you what they want in spades