MSY Archives:Community portal
This is the oldest available source of discussion and speculation for To the Stars, running since early 2013. Much of the most in-depth discussion still takes place here.
A more recent community hub, for those who prefer subreddits to forum threads.
The most recent community, and the most active. Mostly a place for general discussion by people who've read To the Stars, rather than for discussion about the story itself.
More of a community project than an actual community, it's still a very filled-out list of employed tropes.
Hieroynm posts all fanart to his Tumblr. This is a collection of all posts there tagged as such.