Altium Designer, Shortcuts for Viewing, Changing Grid and Snap Setting

Toggle measurement Unit : Q
Accessing Grid menu : G
Changing snap setting : SHIFT + E
Switching 2D and 3 D View : 2 & 3
Fit all objects into view : CTRL + PAGE DOWN
Zoom in around cursor (zooms around cursor, position the cursor first) : CTRL + Mouse-wheel up (or PAGE UP)
Zoom out : CTRL + Mouse-wheel down (or PAGE DOWN)