Driftglobe

Floating sphere in 5e (found in Princes of the Apocalypse) that follows you at 60' and emits light per the light or daylight spell upon command.  Daylight can be used but once per day.  

A different command word causes the orb to float 5 feet off the ground, and keep within 60 feet of you unless physically blocked, using the shortest path. This floating effect ends when any creature grabs it.

Why it's useless

Aside from not having to replenish torches or oil, the only benefit this thing could bring is if it allowed the designated light-bearer in the party to free up a hand from carrying a lantern or a torch while marching down hallways in dungeons and such. That way they could use the freed up hand to hold a shield or keep their weapon drawn.

But it fails on that on two counts.

1. The light spell has a range of just 20', but it is 60' away from you. The Daylight mode brings it to 60', but that only lasts 1 hr and is just once/day.
2. It follows you at 60'. Not very helpful when you're walking down a dark passageway.  If it went ahead of you, it would be useful. But it doesn't.

How a DM could unnerf this item

A DM could transform this item from useless to very useful, by simply allowing it to always float above the character's shoulder instead of 60' behind the character.