The "SmartNav 4" camera from the company NaturalPoint has proven itself for operating the "BeneGrid" software via head control.
It is available for both macOS and Windows. The macOS version is sold by the partner company RJ Cooper & Associates.
It is an infrared-based tracking system including dwell control, with additional options for voice and switch control.
Since macOS 10.15.4 (Catalina), a separate head control has been integrated in the operating system, so that you can work with the integrated camera (MacBook, iMac) or a connected webcam.
Yo can find an introduction to this on YouTube:
