Aharon lived his entire life in righteousness: Megillah 11a
Received the honor of wearing the Choshen Mishpat [Breastplate] in reward for being happy at Moshe's honor: Shabbat 139a
Received the gold-trim of the Altar: Yoma 72b
Aharon's merit protected his other sons from the fatal fate of Nadav and Avihu: Yoma 87a
Aharon's Stick, with its blossoms and almonds, was created on Day 6 of Creation, at Sunset: Pesachim 54a King Yoshiyahu hiding Aharon's staff: Yoma 52b; Keritot 5b
Aharon's response to Moses, explaining why he had allowed the creation of the Golden Calf: Megillah 25b
Whether Aharon contracted tzaraat along with Miriam: Shabbat 97a
Moshe and Aharon acting as the first court for declaring the New Month: Rosh HaShanah 25b
Gideon, Yiftach and Samson are known as the 3 "world lightweights," but their judicial power for their generation is compared to that of Moshe, Aharon and Samuel, the "world heavyweights": Rosh HaShanah 25a-b
Aharon's merit provided the Jews' protective clouds: Taanit 9a
Aharaon died on the First of Av: Rosh HaShanah 2b
Aharon's death helped the community attain Forgiveness: Moed Katan 28a
When Aharon died, the Kenaani marauders attacked: Rosh HaShanah 2b-3a; Taanit 9a
Moses learned from Gd. Moses then taught it to Aharon, and Aharon sat by his side. Moses then taught it to Aharon's two sons, who then sat by their side. Moses then taught it to the elders. Moses then left, and Aharon taught it to the others. Aharon left, and his sons taught it to the others. The sons left, and the elders taught it to each other. This way, each learned four times: Eruvin 54
The two drops of oil which remained on Aharon's beard from the time he was anointed: Keritot 5b
The concerns of Moshe and Aharon that they may have trespassed because of the two drops of oil of anointment that remained on Aharon's beard, and Gd's answer: Keritot 5b
Elazar, Aharon's son
Elazar lost his position of greatness because he ruled in law before Moshe, even though he worded his statement "Gd told this to my uncle." This is why Yehoshua never is mentioned as having needed Elazar's help: Eruvin 63a
The Death of Aharon's Sons - Nadav and Avihu
Nadav and Avihu died for issuing a legal ruling before Moshe, in ruling that they should introduce a fire to the altar: Eruvin 63a
Aharon's merit protected his other sons from the fatal fate of Nadav and Avihu: Yoma 87a
Aharon's sons, Nadav and Avihu, were burned on the inside, but their bodies remained intact: Shabbat 113b
Mishael and Eltzafan carried the coffins of Nadav and Avihu in the desert: Succah 25a-b
Why the korbanot brought after the deaths of Nadav and Avihu were burned: Zevachim 16a-b