I will submit my list of my “top four”, but this does not mean that others were not important or famous. My choices are Jethro, Ruth, Onkelus and Avraham ben Avraham (in chronological order).
Jethro (Yitro in Hebrew) was Moses' father in law. He was a wise and righteous man who advised Moses regarding the establishment of a justice system and merited having a weekly porion of the Torah named for him.
Ruth was the great-grandmother of King David. She is often called “the Mother of Royalty”. Certain laws of conversion are revealed by the the way she became part of the Jewish People. She is well known for her declaration, “Where you go I will go, and where you stay I will stay. Your people will be my people and your God my God." (Ruth 1:16).
Onkelos was a Roman Prince and scholar who lived during the period of the destruction of the Second Temple in Jerusalem. He translated the Chumash (The Five Books of Moses) into Aramaic, the language that most Jews spoke at that time, following the Babylonian exile. The translation helped the people better understand the text. His translation is widely known as “Targum Onkelos”. His work was of such great importance that many people are still diligent when reviewing the weekly Torah portion weekly to include the study of “Targum Onkelos”.
Avraham ben Avraham, an 18th century Polish nobleman born as Count Valentin Potozki, converted to Judaism and was subsequently burned at the stake for refusing to renounce Judaism. Many dramatic and inspiring books and articles have been written about his pure dedication and commitment to Judaism. The Vilna Gaon admired and honored Avraham ben Avraham to an extraordinary degree and was closely involved in “The Righteous Convert’s” life, and instructed him to make the blessing “Blessed are You God… to publicly sanctify His Name” when Avraham insisted on remaining faithful to Judaism.