Often used to control the pointer in a GUI.
Touchpad / Trackpad
Usually used to control the pointer in a GUI.
Trackball / Tracker Ball
It can be used to control a GUI pointer.
Tracker balls are often used by people with limited movement (disabled) or by the very young since they are easier to use than a mouse.
Often used for information terminals in public places e.g. libraries or museums where mice or keyboards may be stolen or damaged.
Since it is so like using a pen, it is very easy to create ‘hand-drawn’ sketches.
Joystick / Joypad
Light pens are rarely used today since graphics tablets and high-quality touch screens provide similar functionality.