VRChat - Create and play in virtual worlds with others
FlightGear - The FlightGear flight simulator project is an open-source, multi-platform, cooperative flight simulator development project. It also simulates space flight in Earth's orbit. It's flight dynamics engine (JSBSim) is used in a 2015 NASA benchmark.
Spatial - Collaborate from anywhere in AR
X-Plane - The world's most advanced flight simulator just got an upgrade. Download the free demo today for Windows, macOS, & Linux.
Gather Town - Spatial video-chat worlds for work and play
Tom Clancy’s H.A.W.X 2 - Tom Clancy’s H.