There are a lot of plugins I like but here are some I think would be good for a hobby community.
Discourse Calendar and Events Is nice as if your community hosts events you can easily organise them and see who’s coming etc. A nice way to bring everyone together.
The Discourse Reactions plugin is simple but it makes posts more fun to engage with if you have a wide variety of emoji’s you can react with.
With Discourse Cakeday you can celebrate users’ anniversaries / birthdays if they choose to add that info to their profile. Nice way for people to feel recognised in your community.