Apple Watch supports Assistive Touch with Pinch, Double Pinch, Clench, and Double Clench gestures to open apps, navigate UI, and bring up action menu.
-Apple Watch Series 4 -Apple Watch Series 5 -Apple Watch Series 6 -Apple Watch SE
Galaxy Watch 4 (running WearOS) supports gestures like Raise Arm, Rotate Wrist Twice, Shake Arm Twice to answer calls, wake watch display, check notifications, and more.
MadGaze Android watch from WatchOut offers more than 30 gestures. This include Finger Snap to take picture or answer calls, tap or knock on surface, tap two fingers, etc.
Wear OS watches like Fossil Gen 6 and TicWatch E3 offer built-in gesture controls. You can tilt to wake and use wrist gestures to scroll through messages, menus, and more with a flick of your wrist