What were the reformers called who helped get the 13th amendment added to the Consititution?

Answer 1

Abolitionists

Answer 2

Abolitionists

With the help of Radical Republicans the abolitionists received their answer by the passing of the 13th amendment in 1865.

Answer 3

They were called the Radical Republicans. They were the ones in control of Congress and who later impeached President Andrew Johnson.

From Wikipedia:
"During the American Civil War, and later into the primary part of Reconstruction, the leading Radicals were Thaddeus Stevens in the House, Charles Sumner in the Senate, and John C. Frémont as the 1864 U.S. presidential candidate of the Radical Republicans. Ulysses Grant ran and was elected as a moderate Republican in 1868. Business interests were hopeful that he would provide stable conditions for Southern investment.

Because they had a majority in Congress, the Republicans pursued impeachment of former southern Democrat Andrew Johnson when he tried to subvert their duly passed legislation."