The Prophet ﷺ used to say between the two prostrations, "O Allah, forgive me, have mercy on me, grant me well-being, guide me, and provide for me."
أن النبي ﷺ كان يقول بين السجدتين: اللهم اغفر لي، وارحمني، وعافني، واهدني، وارزقني.
It was narrated by Abu Dawud (850), Tirmidhi (284), and Ibn Majah (898), all of them through the route of Kamil Abu Ala, who said, Habib bin Thabit narrated to me, from Saeed bin Jubayr, from Ibn Abbas, and he related it. The wording given is that of Abu Dawud, while the wording of Ibn Majah is, the Messenger of Allah ﷺ used to say between the two prostrations during the night prayer, "My Lord, forgive me and have mercy on me, set me right and provide for me, and raise me up."Its chain is hasan because of Kamil Abu Ala, for his hadith is hasan so long as he does not contradict others or bring something that is rejected as coming from him.