Godot itself is open source, which I think has brought a strong community of people to it. My mega-big-ultra project I've been working on since 2013 would be nowhere near as close to where it is now (close to launching crowdfunding/alpha) if I hadn't transitioned to Godot! (I was fighting the UE4 system from the days when it was $20/mo, we linux people really got dealt dirty by Tim Sweeny, with lots of empty promises for linux support)