ALIAS -l is an Event Prefix, and has nothing to do with the command /Alias. /Alias -l does NOT work.
The other identifiers I know that are not listed are as follows. (from what I can recall off the top of my head) Some were removed from the help file, some never even made it in.
$colour() -- now $color()
$lof() -- now $file().size
$inpaste -- an identifier I personally asked to be added. Works in On INPUT and tells you if the text being inputted was from a paste. Compliments the $ctrlenter identifier.
$iaddress, $naddress, $raddress -- now $dns() but $iaddress is still necessary as $dns() doesn't cover that info.
$token() -- now $gettok() and friends.
$mp3() -- now $sound()
$shoe() -- now $sock()
$r() -- short for $rand()
$true, $false, $yes, $no, $cancel -- responses from various functions, similar to $null but not mentioned in the help file.
/XYZZY -- Nothing happens.
The operator !=== is also not mentioned in the help file. It stands for Not-Equals-Case-Sensitive. One might assume !== is correct, but it is not.
That's all for now, I'm sure I'll be adding more as soon as I hit post.