Fediverse

The best thing to do is build the communities here that you are interested in. Do what you can to make them lively and active.

The question as ever remains, though, how does one go about this without coming across poorly? That's always the tricky part of trying to form new groups and communities, because it's not quite marketing but it's in a similar vein to get things going, and it more often than not reads as at best mildly uninteresting or at worst offputting and annoying.