I think the other commenters hit the majority of things to do, but I would also suggest cross-posting your community's posts to a related larger, less niche community (a community, not all related communities, otherwise it looks like spam). If there are multiple options, I suggest alternating between them, to get the widest net.

From what I gather from your community, some larger communities could be tabletop games or bar games. I think there's an active table top games community, I don't think there is a bar games community (might be worth a search to find out).

Good luck on building your community :)