I think it would be helpful to have a list of other communities that are primarily or exclusively about discussion of freedom respecting software games with free cultural assets. I can leave a few other message forum links here, but I believe some forum members have lists of even more communities. And by communities, I don't mean things that have no been posted on or used in years, I mean actual active communities.
I can think of a few off the top of my head.
https://opengameart.org/forums/art-discussion
https://forums.wesnoth.org/
http://www.hedgewars.org/forum
https://forum.minetest.net/