Lack of empirical evidence- Discovery trumps revelation. The incorporeal is immaterial. Benjamin Franklin was a skeptic.
The argument from inconsistent revelations- All religions can't be right, so they're probably all wrong. Sectarian religions are mutually contradictory, internally inconsistent and incoherent. Thomas Paine was a secularist.
The argument from evil- If the gods are real, they have a lot of explaining to do. Thomas Jefferson was a humanist.
The argument from reasonable nonbelief- If the existence of the gods were self-evident, everyone would believe. The burden of proof is on religion. James Madison was a freethinker.