I made SmoothTrack, a no-equipment head tracking app for iOS and Android which lets you control the game camera in sim games (like MSFS 2024 for example) with your head - basically like TrackIR, just without any equipment and for $15 instead of $150. I originally made the app just for myself to save myself the money of buying a TrackIR system, but then /r/flightsim begged me to release it as a full app. Last month, I released SmoothTrack 2.0 which includes basic eye tracking and camera control gestures. https://smoothtrack.app