Ergonomic / Vertical Mouse

Evoluent Vertical Mouse

This one is the best for those with hand injury using the mouse.

They have left-handed version, and wired or wireless.

Orthovia OrthoMouse Wireless Ergonomic Mouse

2017-12-21 saw this on amazon. Not sure what's what.

the reviews seem to be slightly negative.

Anker Ergonomic Mouse

This one is very cheap. There are wired and wireless versions.

EV Ergonomic Mouse

SmartNav Natural Point Hands Free Mouse

You wear a headlamp-like thing to your head, it shoots a lazer pointer, and the screen detects the pointer. So, basically you just move your head slightly to move pointer.

TrackIr 5 Optical Head Tracking System

This one is mostly gamers playing flight simulator games. It is not a mouse substitute, but supplement.

Lots positive reviews on amazon.

Alternatives

You can try trackball. See Best Trackballs 2018

touchpad, see: Input Devices: Mouse, Jog Wheel, Touchpad, Pen Tablet, Trackball, Joystick.

there's also Contour Roller Mouse