I was going to say a pair of quality scissors. Someone gave me a nice pair for Christmas when I was a teenager. At the time, I was thoroughly unimpressed with the boring gift, but 40-odd years later it's still in my desk and regularly used when most other things of my youth are long gone. A related, and cheaper, thing that becomes very handy once you are accustomed to having it at hand is a portable paper trimmer. (https://www.amazon.com/AmazonBasics-Craft-Paper-Trimmer-Inch...)
Along the same line: a good stapler. Just like Milton from Office Space, a proper metal Swingline stapler has been the best in my experience. Unlike that movie, I never found a red one that was as good as a black one.
I still have it over 30 years later, although my need to staple these days is exceedingly rare.
I once cut through a live mains electricity cable with a pair of Fiskars scissors. They blades had holes burned into them, and were very blackened!
I posted an image to twitter and received sympathy from Fiskars but no other comment. I had to go and buy another pair - orange handled, for left-handed people.
(Was obviously not intentional, but I guess the insulated handles helped save me!)