Cron - Cron Calendar.
WebGazer.js - Eye tracking on the browser
zcal - zcal is the fastest way to schedule every meeting for Free and make it personal.
Umoove - Face and eye tracking for mobile devices/gaming
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
Eye Yoga - Improve eyesight, relieve eye strain and prevent presbyopia.