Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
Anti-Federalism
During the period of debate over the ratification of the Constitution, numerous independent local speeches and articles were published all across the country. Initially, many of the articles in opposition were written under pseudonyms, such as "Brutus" (likely Melancton Smith), "Centinel" (likely Samuel Bryan), and "Federal Farmer." Eventually, famous revolutionary figures such as Patrick Henry came out publicly against the Constitution. They argued that the strong national government proposed by the Federalists was a threat to the rights of individuals and that the president would become a king. They objected to the federal court system created by the proposed constitution. This produced a phenomenal body of political writing; the best and most influential of these articles and speeches were gathered by historians into a collection known as the "Anti-Federalist Papers" in allusion to the "Federalist Papers".