I hear all these answers (Ice Arrows, Dominion rod, All-Night mask) but what about, say, the whip in SS? Its useful in some areas but only because they put in un-needed slightly higher then you can reach switches, and for the ancient cistern temple. I used it by far the least in the game, and even though it isnt the leat useful in all LoZ (Icve arrows would take that role) I have to acknowledge that it is really slightly pointless at times. Thoughts? Prove me wrong!
The Master Sword is pretty useless.
Oh yes, least useful item in the entire series. I mean, you only use it to kill virtually every boss and most enemies, and to travel in time.. what uses are those?