Further reports on this subject

Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) said: When the Prophet (peace and blessings be upon him) stayed at my home, I saw that he (peace and blessings be upon him) regularly prayed four rak'ahs before Zuhr. He (peace and blessings be upon him) would say: "When the sun passes its zenith, the gates of heaven are opened, and none of them is closed until the Zuhr prayer has been prayed. So I love that some good of mine should rise up at that hour."
(Allamah al-Haythami said:) I say:
Abu Dawud and others recorded this narration in abridged form.
Al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat.

From Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him), in al-Mu'jam al-Kabir,
this narration is transmitted: He said: The Prophet (peace and blessings be upon him) stayed at my home for a month. I saw that when the sun passed its zenith (the narrator is unsure about one word here), if he was doing some worldly task he would set it aside, and if he was asleep he would wake up. Then he would get up and take a bath or perform ablution, and then pray four rak'ahs in which he would complete the bowing; he would complete them and perform them well, and he would perform them with care. When he was about to leave, I said: "O Messenger of Allah! I have seen that when the sun passes its zenith, if you are doing some worldly task you set it aside, and if you are asleep it is as though you have been woken up. Then you take a bath or perform ablution and pray four rak'ahs, which you complete with care and perform well." The Prophet (peace and blessings be upon him) said: "The gates of heaven and the gates of Paradise are opened at that hour, and at that hour no one is performing this prayer. So I love that some good from me should rise to my Lord at that hour."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and Abu Dawud and Ibn Majah recorded part of it. The chain of this narration contains Ubaydullah bin Zahr, who narrated it from Ali bin Yazid;
both of them have been declared da'if (weak), and both have also been declared trustworthy. The first narration contains Ubaydah bin Mu'attib al-Dabbi, who is matruk (abandoned), except that Ibn Adi said: "Despite his weakness, his hadith is to be written down."

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: When it was midday, the Prophet (peace and blessings be upon him) would go to one of the gardens of Madinah, where water for purification had been prepared for him. If he needed to relieve himself, he would do so; otherwise he would perform ablution. When the sun had declined from the middle of the sky by the length of a sandal strap, he would get up and pray four rak'ahs. He did not recite the tashahhud between them, and he gave the salam after the fourth rak'ah. Then he would get up and come to the mosque. Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: "O Messenger of Allah! What is this prayer that you perform and we do not perform?" The Prophet (peace and blessings be upon him) said: "Whoever of my Ummah performs this prayer, it is as though he has spent that night in worship. It is an hour in which the gates of heaven are opened and in which supplication is answered."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains Nafi' Abu Hurmuz, who is matruk (abandoned).

Sayyiduna Safwan (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever prays four rak'ahs before Zuhr, it will be for him like freeing ten slaves (the narrator is unsure; perhaps the words are:) like freeing four slaves from the descendants of Sayyiduna Isma'il (peace be upon him)."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a group of narrators whose biographies I have not found (written in any book).

Ayman, the freed slave of Ibn Abi Amrah, said: I came to Sayyidah Aishah (may Allah be pleased with her). I was a slave in those days; this was before I was freed. I said to her: "O Mother of the Believers! At which hour did the Prophet (peace and blessings be upon him) pray the most?" Sayyidah Aishah (may Allah be pleased with her) said: "When it was time for the sun to decline, until it had declined."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Abdullah bin Muslim bin Hurmuz, who is da'if (weak).

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: Whenever I came at midday, I found the Prophet (peace and blessings be upon him) praying.
Ahmad recorded it; its chain contains Layth bin Abi Sulaym, who is thiqah (trustworthy), but he is a mudallis (one who conceals defects in the chain).

Sayyiduna al-Bara' bin Azib (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever prays four rak'ahs before Zuhr, it is as though he prayed those rak'ahs in the tahajjud prayer of that night; and whoever prays four rak'ahs after Isha, it will be like praying four rak'ahs on the Night of Decree (Laylat al-Qadr)."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Nahid bin Salim al-Bahili, and there are other narrators besides him, whom I did not find anyone mentioning. (Allamah al-Haythami said:) I say: The hadiths transmitted from Sayyiduna Anas (may Allah be pleased with him) and other Companions about praying after the Isha prayer will come later.

Sayyiduna al-Bara' (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) used to pray four rak'ahs before Zuhr.
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Muhammad bin Abi Layla, about whom there is criticism.

Bashir bin Abi Sulayman narrated from an elderly man of the Ansar, from his father, that the Prophet (peace and blessings be upon him) said: "Whoever prays four rak'ahs before Zuhr, it is like freeing one slave from the descendants of Isma'il."

Bashir bin Salman narrated something similar from Amr al-Ansari, from his father, from the Prophet (peace and blessings be upon him). Al-Tabarani recorded both narrations in al-Mu'jam al-Kabir. The chains of both contain Amr al-Ansari and an elderly man of the Ansar, and I do not know either of them; the remaining narrators of both narrations are thiqat (trustworthy).

Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever prays the Duha (forenoon) prayer, and prays four rak'ahs before Duha, a house is built for him in Paradise."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a group of narrators about whom I have not seen anyone give an account.

Abd al-Rahman bin Humayd narrated from his father, from his grandfather, that the Prophet (peace and blessings be upon him) said: "The prayer of midday (al-hajir) is like the prayer of the night." The narrator said: I asked Abd al-Rahman bin Humayd about the word "hajir", and he said: "When the sun passes its zenith."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators have been declared trustworthy.

Abdullah bin Budayl said: The person who was closest of all to Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) told me that when the sun passed its zenith, Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) would get up and pray four rak'ahs, reciting in them two surahs from the "Mi'in" (the surahs of about a hundred verses). When the muezzins began calling (the adhan), he would put on his garments and go out to the prayer.
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator who is not named.

Al-Aswad, Murrah and Masruq said: Sayyiduna Abdullah (may Allah be pleased with him) said: "No prayer of the day is equal to the prayer of the night, except that the four rak'ahs before Zuhr are different. These rak'ahs have the same superiority over the prayers of the day that prayer in congregation has over praying alone."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; it contains Bishr bin al-Walid al-Kindi, whom a group declared thiqah (trustworthy), and there is criticism of him; the remaining narrators of this report are the narrators of the Sahih.

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) used to pray between Zuhr and Asr.
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Salih bin Nabhan, who has been criticised on the grounds that his memory became confused (ikhtilat), and a group declared him thiqah (trustworthy).