There's of course no single correct list, but I would pick: language (symbolic communication), writing, the scientific method, electricity, the computer.

Other highly consequential inventions: the printing press, the wheel, agriculture, money, the internet.

Notice something subtle. Early inventions extend coordination. Middle inventions extend memory. Later inventions extend reasoning. The latest inventions extend agency. This suggests that human history is less about tools and more about outsourcing parts of the mind into the world.

Refrigeration is a big one

Farming. Animal husbandry. Stirrups. Government. Language. Money/credit/bookkeeping/stocks. Gunpowder. Steam engine. Science. Mass production. Transistor. Logistics.

Also mass communication although that hasn’t turned out so well.

And yeah, call it engineering. Started with the wheel. Thanks for the reminder in thread.

If we're talking about big science&technology categories, I'd say:

Controlled fire (if you can consider it a "man-made creation") -> essential for food and a lot of manufacturing

Wheel -> essential for transportation, but also to make flour (millstones), and a lot of other stuff (e.g. turbines are, basically, specialized wheels)

Controlled electricity and electromagnetism -> artificial light, modern communications, not to mention medical advancements like X-rays

Insulin and pecillin -> millions of lives saved

the printing press -> knowledge becomes easier to spread

If we extend this to all kinds of human "inventions", including law, philosophy, religion, and so on, the list is even longer.

Near real-time communication overseas.

https://en.wikipedia.org/wiki/Transatlantic_telegraph_cable

The demographic impact of medications and vaccines is very significant, it used to take some populations centuries to double their number, now it takes few decades.