One of those... ya never know when you might need it tools...

[mdlbldrmatt135]

https://www.handeeclamp.com/

I picked up a pair of the "blemished" ones a year or so ago, because it looked like it'd come in handy... I've used it a few times now...   though I'd share here.

[Piggiron]

Been more than a few instances where I wish I'd had one. Trying to pinch a net between 2 fingers and getting in a tight spot and cussing when I dropped it.

[34_40]

I had a friend who'd run out and buy every "new" idea tool. I used to tease him about getting the "tool of the month".  Some of them worked as intended and could prove worth having. Some others were simply just a waste (imho)

I don't know if this one is a must have... but I don't believe I'll be finding out.

[TerryWerm]

This is one of those tools that you seldom need but it is handy as can be when you do! 

A couple of years ago I copied a wire clamp tool that I saw somewhere. Nice, easy job on the lathe and the mill. It also is one of those tools that you do not often need but can be a lifesaver when you do. I carry it on the motorcycle along with some wire for those just-in-case moments. I will have to make up some drawings for it and post a thread.