The most used commands I use are probably the simplist as well:
(defun C:ZE ()
(command ".zoom" "e")
(princ)
)
(defun C:Zp ()
(command ".zoom" "p")
(princ)
)
(defun C:qs ()
(command "qsave")
(princ)
)
ZE= Zoom Extents
ZP= Zoom Previous
QS= Qsave
I know they aren't much, but of all the lsp I have put together, they are the ones I use consistently without thought. I hate using another machine without these simple commands loaded up. I feel lost without them at times. ... kinda weird I guess.