The Prophet ﷺ used to say between the two prostrations, "O Allah, forgive me, have mercy on me, restore me, guide me, and provide for me."
حدثنا سلمة بن شبيب حدثنا زيد بن حباب عن كامل أبي العلاء عن حبيب بن أبي ثابت عن سعيد بن جبير
أن النبي ﷺ كان يقول بين السجدتين اللهم اغفر لي وارحمني واجبرني واهدني وارزقني
[Its chain of transmission is daif] Abu Dawud narrated it in the Book of Prayer, Chapter on the Supplication Between the Two Prostrations, no. 850, from the hadith of Zayd bin Hubab with the same wording, and its chain is daif due to Habib bin Abu Thabit's habit of concealing his sources in the chain of transmission. Hakim graded it sahih (1/262, 271), as did Dhahabi, while Nawawi graded it hasan in Adhkar. Part of the hadith has a corroborating narration in Muslim, no. 2697. See also Sharh al-Sunnah by Baghawi (3/164), under no. 667. Baghawi also narrated it from the hadith of Tirmidhi with the same wording.Makhul, may Allah have mercy on him, used to say between the two prostrations, "O Allah, forgive me, have mercy on me, shield me, protect me, and raise me." (Narrated by Ibn Muqri in Mujam, p. 411, no. 1357, with a sahih chain.)