control + up or down arrow

is the same thing as page up or down. useful if you are on a mac or can't find page up or down on a keyboard without glancing at the keypad.

Daring Fireball: Where Keyboard Shortcuts Win

An interesting analysis of some original research Apple did about 20 years ago on whether or not keyboard shortcuts are faster than using the mouse. The research found that although for most tasks using the mouse was actually faster, users consistently reported that using the keyboard was faster. The two notable exceptions to this were when it was possible to the mouse and the keyboard (think ZXCV and apple key when editing text or graphics) or when accomplishing repetitive tasks.