Beam Eye Tracker - Turn Your Webcam into an Eye Tracker
PyGaze | Open source eye-tracking software and more.
AI-Powered Eye Tracking Software For Webcams & 3D Sensors
If you're using Eyeware Beam: 60FPS+ webcam eye tracking was made available for Star Citizen with the latest release, if your webcam supports higher frame rates (e.g. Logitech Brio, Elgato Facecam, ...).
Eye movement tracking with webcam for heat maps and gaze-based control