Narrated from Abu Musa Ashari (RA), the Prophet (ﷺ) used to recite this dua:
اَللَّهُمَّ اغْفِرْ لِي خَطِيْئَتِيْ وَجَهْلِيْ وَإِسْرَافِي فِي أَمْرِيْ وَمَا أَنْتَ أَعْلَمُ بِهِ مِنِّي اَللَّهُمَّ اغْفِرْ لِي جِدِّيْ وَهَزَلِيْ وَخَطَئِيْ وَعَمْدِيْ وَكُلُّ ذَلِكَ عِنْدِيْ اَللَّهُمَ اغْفِرْ لِي مَا قَدَّمْتُ وَمَا أَخَّرْتُ وَمَا أَسْرَرْتُ وَمَا أَعْلَنْتُ وَمَا أَنْتَ أَعْلَمُ بِهِ مِنِّي أَنْتَ الْمُقَدِّمُ وَأَنْتَ الْمُؤَخِّرُ وَأَنْتَ عَلَى كُلِّ شَيْءٍ قَدِيْرٌ
اَللّٰهُمَّ اغْفِرْ لِيْ خَطِيْئَتِيْ وَجَهْلِيْ وَاِسْرَافِيْ فِيْ اَمْرِيْ وَمَا اَنْتَ اَعْلَمُ بِهٖ مِنِّيْ اَللّٰهُمَّ اغْفِرْ لِيْ جِدِّيْ وَهَزَلِيْ وَخَطَئِيْ وَعَمْدِيْ وَكُلُّ ذٰلِكَ عِنْدِيْ اَللّٰهُمَ اغْفِرْ لِيْ مَا قَدَّمْتُ وَمَا اَخَّرْتُ وَمَا اَسْرَرْتُ وَمَا اَعْلَنْتُ وَمَا اَنْتَ اَعْلَمُ بِهٖ مِنِّيْ اَنْتَ الْمُقَدِّمُ وَاَنْتَ الْمُؤَخِّرُ وَاَنْتَ عَلٰى كُلِّ شَيْءٍ قَدِيْرٌ
Allahumm-aghfir li khati'ati, wa jahli, wa israafi fi amri, wa maa Anta a'lamu bihi minni. Allahumm-aghfir li jiddi wa hazali, wa khata'i wa 'amdi, wa kullu dhalika 'indi. Allahumm-aghfir li maa qaddamtu wa maa akhkhartu, wa maa asrartu, wa maa a'lantu, wa maa Anta a'lamu bihi minni. Antal-Muqaddimu, wa Antal-Mu'akhkhiru; wa Anta 'alaa kulli shai'in Qadir
O Allah, forgive me my faults, my ignorance, my immoderation in my concerns. And Thou art better aware (of my affairs) than myself. O Allah, grant me forgiveness (of the faults which I committed) seriously or otherwise (and which I committed inadvertently and de- liberately. All these (failings) are in me. O Allah, grant me forgiveness from the fault which I did in haste or deferred, which I committed in privacy or in public and Thou art better aware of (them) than myself. Thou art the First and the Last and over all things Thou art Omnipotent.