As good a place as any to start, with a topical, alphabetical exploration of the Church of Jesus Christ of Latter-day Saints.
Aaron, brother of Moses. Hebrew, Aharown.
One might say the Restored Gospel brings his name into more prominence than was typical in the rest of Christianity. Other Christians tend to consider the priesthood of Aaron as an Old Testament relic, fulfilled along with the rest of the Law.
But modern revelation in the Doctrine and Covenants goes into some detail about that priesthood and its relevance in the Church. I will treat that priesthood in a separate blog entry.
It is interesting that although the resurrected Moses appeared to Joseph Smith, no mention is made of Aaron having done so.
Aaron and Moses form one of the more positive sibling pairs in the scriptures, as opposed to Jacob and Esau, Joseph ben Israel and his brothers, Nephi and Laman/Lemuel, and Rachel and Leah. A model for Joseph Smith and his brother, Hyrum.