General (most window types)

Toolbar T
Properties N
Add Object/Node Shift + A
Delete X or Delete
Search F3
Move G
Scale S
Rotate R
Rotate along axis R then X/Y/Z
Rotate along local axis R then X,X/Y,Y/Z,Z
Trackball Rotate R, R
Precise movement Shift (hold)
Incremental movement Ctrl (hold)
Duplicate Shift + D
Duplicate Linked Alt + D
Hide H
Unhide All Alt + H
Hide all Except Selected Shift + H
Annotate D (hold) + LMB (drag)
Erase Annotation D (hold) + RMB (drag)
Quick favs menu Q
Orbit MMB
Pan Shift + MMB
Zoom In/Out Scroll or Ctrl + MMB
Fly Shift + ~

View (3D viewport)

Numpad views: