#pinkyandspiky is niche community/ Drawing Contest created by @organduo. I don't consider my account here big but if I am not mistaken it is one of the biggest among contest participants. Despite that most of those people are constantly making entries in this contest. I believe that this is a sign that most of them intend to be here for a long time. I am sure that they could use some help in growing bigger.
I could also mention Hive Gaming... But that would mainly be because I am quite active there. So #pinkyandspiky is probably closer to what you are looking for.
Thanks for your recommendation, much appreciated.