Ulla described with the title, "Ulla Rabbah [the Great]": Kiddushin 31a
Anecdotes involving other sages
Ulla challenged Rav Chisda's statement by borrowing a verse from Proverbs 10, calling it 'like vinegar to the teeth and smoke to the eyes': Taanit 4b
Ulla responding to a statement by Rabbi Abba, "This man is [speaking] as though he has never learned!": Bava Metzia 11b
Ulla called Rabbi Elazar, "Master of Israel" [because of a case in which Rabbi Ami witnessed Rabbi Elazar correctly identify a type of blood from the genitals, by the smell of the blood]: Gittin 19b; Niddah 20b
Called a "Great Man" by Rav Kahana: Rosh HaShanah 22b
Ulla responded to an explanation by Rava, "Ada Tehei," "Thus it should be.": Makkot 21b
When Ulla was in the house of Rav Menasheh, a man came and knocked at the gate on Shabbat. Ulla said, "May this man's body be desecrated, as he desecrated Shabbat!" Rabbah responded that only musical sounds are forbidden on Shabbat: Eruvin 104a
Ulla waited for Rav Nachman to leave, before arguing against his ruling: Bava Kama 12a
Ulla grew upset with Rabbah Bar Bar Chanah for mis-stating a quote from Rabbi Yochanan, and Rabbah Bar Bar Chanah corrected it intuitively: Pesachim 53b-54a
Ulla's travels
Ulla came to Pumbedita and saw a garment which he identified as being the shade of black which, in a fluid, may be [menstrual] blood; the local people then bought every thread of the garment from its owner, to have for themselves: Niddah 20a
Ulla came to Pumbedita and refused to examine a case of menstrual blood, because Rabbi Elazar had refused to examine a case when in Rabbi Yehudah's town: Niddah 20b
Ulla, en route to Israel, witnessed one traveller killing another. When Ulla was confronted, he encouraged the murderer, to save his own life. When Ulla told Rabbi Yochanan what had transpired, Rabbi Yochanan approved of his act, but wondered at how this could have happened in Israel, if rage was to be an element of Exile. Ulla responded that they had not yet entered Israel at the time: Nedarim 22a-b
Ulla's prediction of rain in Bavel based on the clouds, and his reaction when the prediction did not come true: Taanit 9b
Ulla was upset at the rabbis of Pumbedita, who shook out water from garments on Shabbat; Rav Yehudah said, "Shake them in Ulla's face; [we may do it because] we aren't careful about their cleanliness": Shabbat 147a
Ulla was amazed at the cheapness of dates in Bavel, and he couldn't understand why people there didn't eat cheap dates and learn Torah - but then his digestion was affected by the dates and he was amazed that Babylonians could learn Torah at all: Taanit 9b
Sets of statements by Ulla
Set of statements, quoted by Rabbi Chiyya Bar Ami: Berachot 8a
Set of statements quoting Rabbi Elazar: Bava Kama 11a-12a