Any sort of a list would include the printing press, good clocks, coal power, clean water, the microscope/telescope and the integrated circuit.
Every so often an invention comes along that doubles or triples the size of the universe. Such an invention was Johannes Gutenberg's development of moveable, reusable type that revolutionized printing. Before Gutenberg printing was done with plates and books were laboriously, expensively and rarely produced. Most people in the Middle Ages were illiterate. Even the parish priest, an important community leader, was only marginally literate. The few Bibles were often chained to a reading stand in the church and the word of God was whatever the priest said it was. Some contend that Gutenberg is responsible for the Reformation. When you can read the word of God you can see for yourself what it says. The inevitable happened. People disagreed as to what the Bible said, and people disagreed as to what the words of the Bible meant. The path for multiple and personal interpretations was now open.
Whether some environmentalists like it or not the backbone of industrialization is fossil fuels and the leading fossil fuel is coal. "Big Alice" is still on the job in New York City. Big Alice is the largest generator in the New York system and Big Alice runs on coal. In 1709, Abraham Darby succeeded in using "charred" coal instead of wood charcoal to produce iron. This new fuel, "coke" would change the production of steel forever and high-quality steel, not iron, is the basis for modern structures, machinery and countless manufactured products. In China there will be 700 coal-powered power plants opened in the next ten years. Coal production is on the increase worldwide and it may be that the conversion of coal to the cleaner fuel, natural gas and the scrubbing of coal to cut pollution will be a major part of the world's energy future.
Clean water is both a current and a future frontier. Half of the world's population does not have clean water. There will never be a job shortage for civil engineers. Without water for bathing, industry, sanitation and thirst we would all die quickly and gruesomely.
As you travel form place to place how do you know where you are? The sun moves across the sky. Really? Sailors could shoot the position of the sun with a sextant and the astrolabe, one of the most useful inventions of all time because it is also a mathematical device could be used to plot the position of the stars at night. But what do you do if there are storms, clouds or darkness? It is only with the development of accurate clocks that one sees the development of the concept of longitude. Now one could draw the imaginary meridians on the earth's surface and really plot the path of the sun and finally determine how far east or west you really were.
In the 15th century, two Dutchmen, Anton Von Leeuwenhoek and Hans Lipperhey doubled the size of the universe with the invention of the microscope and the telescope respectively. One device presented things that were too small to see, and the other invention presented things that were out beyond our range of sight. Perhaps it is now hard for us to imagine that up until the invention of the telescope astronomy was performed with the naked eye.
The integrated circuit is the basis for the computer age which has moved millions from a production economy to an information and service economy and also had the side effects of producing people who check their cell phones an average of forty times a day and who spend more than six hours a day devoted to screen viewing time. As late as the Vanguard satellite program of the 1960's circuits were done by hand. Gone are the days of the hand-soldered connection. Circuits can now be printed. Remember too that Moore's Law is not in effect. Moore's Law says that the total capacity of integrated circuits doubles every two years.
The future? That's simple. All we want is a technology that is faster, more efficient, cheaper, more durable, environmentally sound and of course, more humane.