MButton (Middle button) - middle mouse button (or mouse wheel)
User Perspective
1 NumPad — Front Orthographic
3 NumPad — Right Orthographic
7 NumPad — Top Orthographic
5 NumPad — User Orthographic/User Perspective
Ctrl + Alt + Q — Quad View
Ctrl + 1 NumPad (left).
Ctrl + 3 NumPad (back).
Ctrl + 7 NumPad (bottom).
Ctrl-MMB / NumpadPlus / NumpadMinus
LButton - left mouse button (Selecting an object)
RButton - Right mouse button (Object context menu)
Blender start page