Abdullah ibn Abbas (رضي الله عنه) was a great companion and a great scholar. In fact, the Prophet (صلي الله عليه وسلم) made du’a for him, that Allah (سبحانه وتعالى) grants him knowledge of the deen.
Even more amazing then this, Ibn Abbas narrated that the Prophet (صلي الله عليه وسلم) once made du’a and said, “O Allah! teach him wisdom (i.e. the understanding of the knowledge of Qur’an).” [Bukhari 5/57/100] This is why his tafseer carries a heavy weight, even today, more then a millenium after his death. This is why, if you ever find tafseer by Abdullah ibn Abbas, seize it and don’t let go. Ever.
You can find a lot of points he made in Tafseer ibn Katheer.
May Allah (سبحانه وتعالى) grant us better knowledge of Islam and the tawfiq to act upon that knowledge, ameen!