Sh -> startup = extensions off
Space Bar -> startup = extension off via extension manager
Alt-Cmd -> startup = rebuild desktop file
Cmd-Alt-Sh -> startup = bypass startup disk  (Cmd-Sh-Opt-Del???)
Sh-C -> startup = startup from Apple SCSI  CD-ROM
Cmd-Alt-P-R -> startup (after beep) = reset PRAM

Cmd-Power = Start debugger (G to rescue system)
Cmd-Ctrl-Power = Force restart
Sh-Cmd-Ctrl-Power = Reset on PBook
Cmd-Alt-P-R = Restart with PRAM reset
Cmd-Alt-Esc = Force quit
Cmd-.(dot) = Quit operation
Cmd-Sh-K = Clean install

Cmd-Sh-Ctrl-3 = copy desktop into clipboard
Cmd-Sh-4 = copy part of the desktop into a file (space bar to cancel)
Cmd-Sh-4-Caps = copy a window into a file
(same as above but pressing Ctrl while clicking = copy into the clipboard instead into the file)
N.B.  pictures are stored in the startup disk!!!