The rabbinical court in Usha permitted a husband to repeal his wife's sale of nichsei melog, where she predeceases her husband: Ketuvot 50a; Bava Metzia 35a
The rabbinical court determined to not ex-communicate a Chief Justice for sinning once: Moed Katan 17a
The rabbinical court in Usha instituting that if a man gives all of his assets to his children during his lifetime, he and his wife are still supported from those assets [because we assume that was the father's intent]: Ketuvot 49b-50a
The rabbinical court in Usha capped tzedakah at 20% of one's income: Ketuvot 50a [per Tosafot אל; Rashi seems to say 20% of assets]; Ketuvot 67b [sounds like assets]
The rabbinical court in Usha enacted that fathers should gently encourage their sons to learn Torah until the age of 12, and then become more fierce if their sons still refuse: Ketuvot 50a
A series of comments from Rabbi Ila'a related to enactments of the rabbinical court in Usha; Rav Simi bar Ashi noted that the first statement came from Rabbi Ila'a citing Reish Lakish citing another sage, the second came from Rabbi Ila'a citing Reish Lakish, and the third was just from Rabbi Ila'a himself: Ketuvot 49b-50a
Rabbis of Caesaria
Their mathematical calculations: Succah 8a-b
Rabbis of Yavneh
When the Court was in Yavneh: Rosh HaShanah 31a-b
They said that the main factor in an individual's service of Hashem is his Intention: Berachot 17a
On whether Torah will ever be forgotten from the Jews: Shabbat 138b
In honor of the miracle of the non-decay of the bodies of the Betar rebels in the years before their burial, and in honor of the granting of permission for their burial, the Rabbis of Yavneh established a fourth blessing, "HaTov VeHaMaytiv," for the Blessing after Meals: Taanit 31a
How they used to pray the "Musaf" service of Rosh HaShanah: Rosh HaShanah 32a