Stephen's List: 19

Adam Smith (of course)
Henry Hazlitt
Eugene von Baum-bawerk
Ludwig von Mises
Jean-Babtiste Say
FA Hayek
Ayn Rand
Milton Friedman
Thomas Jefferson
Aristotle
Cyrus of Persia
Thomas Sowell
Murray Rothbard
F. Bastiat
Charles Darwin... well... his impact w.r.t. freedom might have been delayed, but impacted none-the-less
W.H. Hutt
Lysander Spooner