For AutoCAD veterans users I have listed all shortcuts of keyboard.
See all keyboards shortcuts and use them.
F1 - displays help
F2 - displays text window
F3 - switches object snaps
F4 - toggles table mode
F5 - toggles isometric planes
F6 - toggles DUCS (switches coordinate display, till A2006)
F7 - toggles grid display
F8 - toggles ortho mode
F9 - toggles snap
F10 - toggles polar tracing
F11 - toggles object tracing
F12 - toggles dynamic input (2006+)
ESC - cancel changes, cancel grips
TAB - cycles osnaps
SHIFT - (on object selection) removes objects
DEL - erases objects (hold when pointing)
Ctrl+0 - toggles clean-screen mode (2004+)
Ctrl+1 - displays Properties window
Ctrl+2 - displays DesignCenter window
Ctrl+3 - displays Tool palette (2004+)
Ctrl+4 - displays Sheet Set Manager, or Content Manager (2005+, ADT2004)
Ctrl+5 - displays Info Palette, or Project Navigator (2005-2007, ADT2004)
Ctrl+6 - displays dBConnect window
Ctrl+7 - displays Markup Manager (2005)
Ctrl+8 - displays Quick Calculator (2006+)
Ctrl+9 - shows/hides Command line (2006+)
Ctrl+A - selects all thawed objects (2002)
Ctrl+Shift+A - toggles group selection (group/single)
Ctrl+B - toggles snap
Ctrl+C - copies content to Clipboard
Ctrl+Shift+C - copies with reference point
Ctrl+D - toggles coordinates display (dynamic UCS, till 2009)
Ctrl+E - switches isoplanes
Ctrl+Shift+E - pull a region to 3D (PRESSPULL, since 2010)
Ctrl+F - toggles osnaps
Ctrl+G - toggles grid display
Ctrl+H - toggles Pickstyle (group and hatch selection)
Ctrl+Shift+H - toggles Palettes display (2009+)
Ctrl+I - toggles coordinate display (2009+)
Ctrl+J - repeats the last command (Enter)
Ctrl+K - displays the Hyperlink dialog
Ctrl+L - toggles Ortho mode
Ctrl+N - starts new drawing
Ctrl+O - opens a drawing
Ctrl+P - print a drawing
Ctrl+Shift+P - toggles Quick Properties display (2009+)
Ctrl+Q - quits AutoCAD (2004+)
Ctrl+R - switches to the next viewport
Ctrl+S - saves drawing
Ctrl+Shift+S - saves drawing as (2004+)
Ctrl+T - toggles the Tablet mode
Ctrl+U - switches polar tracing
Ctrl+V - pastes the Clipboard contents
Ctrl+Shift+V - pastes contents as block
Ctrl+W - toggles object tracing
Ctrl+X - cuts contents to the Clipboard
Ctrl+Y - redoes the undone action
Ctrl+Z - undoes the last action
Ctrl+PgDn - switches to the next layout (2004+)
Ctrl+PgUp - switches to the previous layout (2004+)
Alt+F8 - VBA macros
Alt+F11 - VBA editor
Temporary override keys (2006+):
Shift - switches ortho mode
Shift+- switches dynamic UCS mode (2007+)
Shift+)- switches object tracing mode (2007+)
Shift+. switches polar mode
Shift+A - switches osnaps
Shift+E - switches endpoint osnap
Shift+C - switches center osnap
Shift+D - disables osnaps and tracing
Shift+M - switches middle osnap
Shift+Q - switches object tracing osnap
Shift+S - enables osnap override
Shift+W - starts SteeringWheel (A2009+)
Shift+X - switches polar tracing
CTRL+mouse - cycles selection of overlapping objects (till 2006)
Shift+space - cycles selection of overlapping objects in 2D (2007+)
CTRL+space - cycles selection of overlapping sub-objects in 3D (2007+)
CTRL+ALT - extrudes the selected region into 3D - PRESSPULL (2007+)
CTRL+arrow - moves cursor
Arrow up/down - command history
CTRL+SHIFT+letter - goes to the property in the Properties window
ALT+down arrow - opens a list in the Properties window
ALT+up arrow - closes a list in the Properties window
Of course all the Windows shortcut keys remain active as well (Ctrl+Tab, Ctrl+F3, Ctrl+F6 etc.). Other shortcuts may be defined as user keys in the ACCELERATORS section of your AutoCAD menu. Since AutoCAD version 2006 you can also use CUI to define so called temporary override keys.
Thanks CADFORUM.CZ