Can a reliable source for the authentic sayings and wisdom attributed to Imam Ali, may Allah be pleased with him, be provided?

There is no specific book dedicated to the authentic sayings attributed to Ali (may Allah be pleased with him). The books "Nahj al-Balagha" and the poetic "Diwan" attributed to him are not authentic. Instead, one can refer to well-known books that transmit beneficial sayings of the righteous predecessors (Salaf), such as "Rawdat al-'Uqala wa Nuzhat al-Fudala'" by Ibn Hibban, and "Bahjat al-Majalis wa Uns al-Majalis" by Ibn 'Abd al-Barr.