Legal Borderlines for various violations, for receiving punishment: Yoma 80a
The prophets' analysis of a verse, to produce the mitzvah of Reading the Purim Story: Megillah 14a
Identifying the months of the year, for the holidays: Rosh HaShanah 7a
The special letters used at the end of words in Hebrew: Shabbat 104a; Megillah 2b-3a
Establishing the recitation of Hallel-Prayer to pray to be saved from danger: Pesachim 117a
Establishment of the Shifts Representing the Nation on the Daily Offerings: Taanit 26a, 27a
Established a certain number of the shifts of Kohanim serving weekly in the Temple: Taanit 27a-b
Redistributed the shifts of Kohanim after the return for the Second Temple: Taanit 27a-b
Established specific dates and donors for the Wood Used on the Altar: Taanit 28a
Recitation of Hallel on 18 specific days [21 in exile] is an Institution of the Prophets, and treated as a Biblical Law: R. Taanit 28b "Minhag"
The practice of parading with the Willow Branch on Succos in the Temple: Succah 44a