What myths and poems of Ancient Greece talk about camaraderie, friendship, loyalty, devotion?

Partnership is referred to in the myth of the Trojan War. Then there was a strong friendship between Achilles and his brother Patroclus. We can say that Patroclus himself was a student of Achilles. True, one day Patroclus came out to battle the Trojans, who was dressed in the armor of Achilles. The enemy mistook him for the real Achilles. Then the Trojan prince Hector went out to fight with him, who was able to defeat and mortally wound the young man. Achilles bitterly mourned the death of his brother, after which he took revenge on Hector.