Who was the only US Presidential candidate (after the 12th Amendment) to receive all the electoral votes except one?

The United States presidential election of 1820 was the ninth quadrennial presidential election. It was held from Wednesday, November 1, to Wednesday, December 6, 1820. It was the third and last United States presidential election in which a candidate ran effectively unopposed (the previous two unopposed presidential elections were those of 1788–89 and 1792, in which George Washington ran without serious opposition). President James Monroe and Vice President Daniel D. Tompkins were re-elected effortlessly and captured all but one electoral vote. The failing Federalist Party did participate in the election of 1820 by fielding a serious vice-presidential candidate (Richard Stockton), but was unable to nominate a national candidate for president. It was never able to participate again in any federal election.

George Washington got 100% but elections of 1789, 1792, 1796, and 1800 took place before the 12th Amendment and thus each elector had two votes (but had to vote for two separate people).