FlyByWire Simulations community behind the popular A320 add-on for Microsoft Flight Simulator.
Built around FlyByWire's free Airbus add-ons for Microsoft Flight Simulator, this is one of the larger flight-sim communities online. Members get installation help, report bugs, and dig into the systems-level detail that makes the A320 realistic. It draws serious simmers who enjoy learning the aircraft almost as much as flying it.