Musannaf Ibn Abi Shaybah

Hazrat Harith says that Hazrat Ali (may Allah be pleased with him) used to say between the two prostrations: O my Lord! Forgive my sins, have mercy on me, grant me strength, and grant me elevation.

Hazrat Mak’hool used to say between the two prostrations: O my Lord! Forgive my sins, have mercy on me, grant me strength, and provide me with sustenance.

Hazrat Umm Salamah used to say between the two prostrations or between two rak'ahs: O Allah! Forgive me, have mercy on me, and grant me guidance to the straight path.

Hazrat Ibn Tawoos narrates that my father used to recite a lot between the two prostrations.

Hazrat Ata states that the Noble Prophet (peace and blessings be upon him) used to say "Astaghfirullah (I seek forgiveness from Allah), Astaghfirullah (I seek forgiveness from Allah)" between the two prostrations.

Ibrahim says that there is no specific supplication prescribed to be recited between the two prostrations.

Hazrat Mansoor says that I asked Ibrahim whether I should recite anything between the two prostrations? He replied, no.