That's an .. interesting request.

What are you hoping to achieve by finding such a community?

I am not sure what's unique to side-project developers besides the fact that they are often intrinsically motivated.

IndieHackers has a lot of people developing stuff on the side, but the clear focus there is to make money off it at some point in time.

I think you need to specify what you want from such a community for us to make better suggestions :)

> What are you hoping to achieve by finding such a community?

Being around motivated people trying to create something in their spare time is a good thing.

> IndieHackers has a lot of people developing stuff on the side, but the clear focus there is to make money off it at some point in time.

Well, making money is not the motivation.

I don't think I have seen such a community. The closest thing I can think of are old-school bullet in board of the early 2000s that were kind of like this.

Sorry for not being more helpful.