بسم الله الرحمن الرحيم
I was engaged in a discussion with a Sunni brother and he requested that I bring forward ahaadith whose chains are strong by our own standards regarding the very explicit appointment of Imam Ali (عليه السلام) by the Prophet (s). What follows is some research I've collected. I have not personally graded these chains nor have I even confirmed their strength; most of these ahaadith are graded by Ayatollah Zanjani, some by Ayatollah Aasif Muhsini or others. At any rate, I request the brothers here to post in the comments if they have anything to say about the cha