Explanation of Ramban - 25:6 - debate between Rashi and Ibn Ezra whether Keturah was Hagar, debate between Ibn Ezra, Radak and Ramban whether Keturah and Hagar were wives or concubines, and debate between Rashi, Rambam and Ramban what a concubine is in halacha.

Explanation of Ramban - 12:10, 12:11, 20:2, 20:12 - discussion of Rashi, Ramban and Ran's approaches to the two incidents with Pharoah and Avimelech where Sarah is taken by the king, and the differences between them

Explanation of Ramban - 12:7, 15:1, Shemos 12:40 - discussion between Rashi, Tosafos, Ibn Ezra, Ramban and Vilna Gaon, whether Bris Bein Habesarim (ch. 15) happened when Avraham was 70 years old, before Lech Lecha (12:1), or afterwards when he was 75 years old

Explanation of Ramban - 1) 6:18 - debate between Rashi, Ibn Ezra and Ramban what the covenant mentioned to Noach is, 2) 9:12 - debate between Rashi/Ibn Ezra vs. Rav Saadia Gaon/Ramban (and other commentators) whether rainbows are a natural occurence or a miraculous event

Explanation of Ramban - 1) 4:17 - did any of Cain's descendants survive the flood, 2) 4:22 - three views in the midrash what was significant about Naamah, 3) 4:23 - debate with Rashi/Ibn Ezra why Lemech's wives separated from him.

Explanation of Ramban - 1:6, 1:8, 1:10 - debate between Rashi/Ibn Ezra vs. Rambam/Ramban whether the Shamayim in verse 1:1 is the spiritual Heavens or the physical Sky

Explanation of Ramban - 20:10, 20:11, 29:10 - debate between Rashi vs. Rambam/Ramban whether Canaanite nations can surrender, and discussion of why the Gibeonites had to lie to surrender and not do so openly? Rambam, Tosafos and Ramban's answers.

Explantion of Ramban - 23:5, 23:7 - debate between Ibn Ezra and Ramban whether Moav gave the Jewish people food and water, and what it means not to offer them peace.