Those don't exist. There is something called the "Reddiquette" which is by the community and completely informal.
Subreddits owned by companies is the new normal and if you look at games, most reddit users these days even prefer it to community-run ones. Not uncommon to have two subreddits at a launch of a game and the unofficial one will always "lose".
Besides that, Reddit itself reaches out to brands & product owners and influencers to make official subs for them, managed by those entities then.
Subreddits are the new Facebook Groups and Reddit is completely "mainstream". I wonder what's next in a couple of years. Maybe we can go back to forums :)