Three minimalist things that should be more popular than they are...

Spork. I don't know why a titanium spork is such a fun thing to own but it is.

Maybe it is because what you have is the idealized form of a piece of technology, the derivation of one of human's oldest tools. In this iteration the spork is as tough as steel, light, non-toxic, manages hot food without a problem, scoops up yogurt, soup, stew. Heck, you could dig an escape tunnel with it. Did I mention it is made out of the same material as the SR-71?

Zippo. When the hardcore dick is interviewing the busty blonde for an exciting case, he lights his filterless Lucky Strike with a Zippo. Of course, if eating utensils are old, fire is human's oldest tool. What better way to get that campfire going, or light the Molotov to toss at the surging zombie hordes, than a shiny cool lighter. Bonus: learn some tricks.

Esperanto. Ok, this isn't a "thing" per se, but a language. Well, an invented language. In 1887 a linguist named Zamenhof came up with the idea that humanity should all speak a common tongue, and from his efforts was born Esperanto (his first impetus was to revive Latin, but nobody was keen on that). While there are many people who study and practice Esperanto, my guess is, there are more speakers of Klingon.