Giving a third as an extra share after the fifth is taken out

It is narrated from Sayyiduna Habib bin Maslamah al-Fihri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) would give a third as nafl (extra reward) after taking out the fifth (khums) (from the spoils).
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Muhammad bin Abi al-Mujalid: The people of the mosque sent me to Sayyiduna Ibn Abi Awfa (may Allah be pleased with him) to ask him what the Prophet (peace and blessings be upon him) did with the food obtained at Khaybar. I went and asked him this very question: Did he (peace and blessings be upon him) take out a fifth (khums) from it? He said: No, it was less (significant) than that; whoever among us needed something would take from it according to his need.
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Abu Barzah al-Aslami (may Allah be pleased with him) that the Arabs used to say: Whoever eats bread becomes fat. When we conquered Khaybar, we drove them away from their bread (that is, they abandoned their meal and fled). I sat down at a loaf and ate from it until I was full, and then I began looking at my two sides to see whether I had become fat (straight away) or not.
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

Abd al-Rahman bin Abi Layla narrates from his father: I was present with the Messenger of Allah (peace and blessings be upon him) at the conquest of Khaybar. When the enemy was defeated, we entered their encampments, and the people seized the livestock (sheep and goats) they found there. Only a short while had passed when the cooking pots began to boil (with meat). When the Messenger of Allah (peace and blessings be upon him) saw this, he (peace and blessings be upon him) ordered the pots to be overturned (so that no one would eat before the proper distribution). Then he (peace and blessings be upon him) distributed among us and allotted one goat for every ten men.
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Tha'labah bin al-Hakam (may Allah be pleased with him) that he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Plunder (plundered goods) is not lawful, so overturn the cooking pots." In the same way, Ghundar and Ibn Abi Adi narrated it from Shu'bah, and they mentioned that Tha'labah heard it directly from the Prophet (peace and blessings be upon him).
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it because of the narration of Simak bin Harb, for he once narrated it from Tha'labah bin al-Hakam, from Ibn Abbas, from the Prophet (peace and blessings be upon him).