8. The Hair Picks - Double Dragon Neon
The Hair Picks in Double Dragon Neon will barely be used by anyone actually trying to win the game. Throwing them only does a single point of damage to the enemy they hit, making it infinitely less useful than just using your fists like god and the developers intended.
However, it does have one benefit, even if it is completely unhelpful: the hair pin pins to the enemy's hair. This doesn't aid you in any way, but it is strangely amusing to do, just to see how it rests in the follicles of every foe you face.
Also, throwing a pick at each individual enemy nets you an achievement, so the developers did give you some kind of vague usage out of it. If you aren't seeking a platinum for the game, though, you will likely never, ever use this particular weapon - and that isn't exactly a bad thing.
While it's profoundly unclear why the development team would go to the effort of creating a weapon that is totally useless, it's doubly amusing for its total lack of functionality.