When the Prophet ﷺ uttered salutation at the end of the prayer, he used to say: "O Allah, forgive me my former and latter sins, what I have kept secret and what I have done openly, and what I have done extravagance; and what You know better than I do. You are the Advancer, the Delayer, there is no god but You." (Using translation from Abū Dāʾūd 1509)
أَنَّ رَسُولَ اللهِ ﷺ كَانَ مِنْ دُعَائِهِ اللهُمَّ اغْفِرْ لِي مَا قَدَّمْتُ وَمَا أَخَّرْتُ وَمَا أَسْرَرْتُ وَمَا أَعْلَنْتُ وَإِسْرَافِي وَمَا أَنْتَ أَعْلَمُ بِهِ مِنِّي أَنْتَ الْمُقَدِّمُ وَأَنْتَ الْمُؤَخِّرُ لَا إِلَهَ إِلَّا أَنْتَ