Dune Legacy - Dune Legacy is an effort by a handful of developers to revitalize the first-ever real-time strategy game.
X-Plane - The world's most advanced flight simulator just got an upgrade. Download the free demo today for Windows, macOS, & Linux.
Zero-K - Do you want epic battles?
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.
Warzone 2100 - Join "The Project" to restore humanity's synaptic-link technology after nuclear war...
Digital Combat Simulator - Digital Combat Simulator is a Free-to-play, Single and Multiplayer Combat Flight Simulation developed by Eagle Dynamics and published by The Fighter Collection.