Whats a subreddit/slack/substack that you rely on?

Twitter communities can be amorphous and the community at an office can be great until you switch jobs, what's a community that you rely on to give you answers, support or encouragement?

subreddits (I really love the community on r/unity3d)

substacks (I spent a while replying to tons of stuff on Stack Overflow but I know some people are in to particular substacks

Slacks?

Let me know in the comments