Among a lot of lesser lights, some golden oldies.
For beginners, the Austrian school of economics started in the 1880s with Carl Menger, key figures in the 20th century were Ludwig von Mises, Fritz Hayek, Murray Rothbard, Israel Kirzner and Ludwig Lachmann. There was a revival of the movement in the 1970s with a series of conferences in strange places.
The Austrians adopt an evolutionary or ecological approach to social and economic systems to emphasise the role of individual initiative and planning in a framework of traditions, organizations and institutions (especially markets). They were virtually buried in professional circles by the rise of Keynes and mathematical economics. The Austrians are skeptical of mathematics and they tend to be robust free traders and so they were dismissed for many years as unscientific and reactionary. A head count in the professional association in the US indicated that they are out-numbered by other schools by 50 to 1, despite robust growth since the revival of the 1970s.