Rabbi Yishmael sat up for the Recitation of Shema, to prevent students from misunderstanding Rabbi Elazar Ben Azariah's leaning: Berachot 11a
Rabbi Yishmael was an expert in Talmud which dealt with issues that don't deal with law [Aggadata]: Moed Katan 28b
When an anonymous student cites Rabbi Yishmael in front of Rabbi Akiva, that is Rabbi Meir: Eruvin 13a
Told a writer of Amulets, who had dunked them in water when he saw Rabbi Yishmael coming, that the latter sin was worse than the former: Shabbat 115b
Rabbi Tarfon, Rabbi Yosi HaGelili, Rabbi Elazar ben Azaryah and Rabbi Akiva attempting to console Rabbi Yishmael on the loss of his sons: Moed Katan 28b
Rabbi Yishmael told Rabbi Ilai not to question a verdict he had rendered, because he had already permitted it. In fact, he had been correct, and Rabbi Ila'i had not heard the whole statement: Gittin 6b
Rabbi Akiva said that a student's Halachic statement, citing Rabbi Yishmael, was not actually something Rabbi Yishmael had said, but the Halachah would follow that student anyway. He either said this to make a point of encouraging students to think independently, or as a simple statement that he agreed with that student's thinking: Eruvin 13a
Rabbi Yishmael warning Rabbi Meir about the seriousness of writing a Torah scroll, and Rabbi Meir's response: Eruvin 13a
Rabbi Meir tried to learn before Rabbi Akiva, but Rabbi Akiva was too sharp, and so he learned before Rabbi Yishmael, and then before Rabbi Akiva: Eruvin 13a
