Anything from the hand-axe to the quantum computer.
Deliberative Thought ie Why?, The first questions. Without that, no stone-axe or flint knives. Other animals use objects as tools. However there is a tremendous gulf between a stone being used like an axe and a stone deliberately shaped into even the most primative axe. The sheer number of perceptual and cognitive efforts required is staggering. I know it is difficult for most people to wrap their heads around, but you need thought tools for thought experiments, and thought experiments are prerequisites for effecting change in one's ecology socially and materially.
Electricity. Without it you'd have no modern society.
Chocolate....chocolate coated anything.
I have to say the best thing ever created by man (human race), is just one thing, Coffee! 2nd would be bacon.
The Microwave. Nothing says "I don't feel like cooking, but don't wanna go out." Like nuking some kind of food