Sayyid Al-Istighfar

س (1227) مَا هُوَ سَيِّدُ الِاسْتِغْفَارِ؟
جـ (1227) اللَّهُمَّ أَنْتَ رَبِّي، لَا إِلَهَ إِلَّا أَنْتَ، خَلَقْتَنِي وَأَنَا عَبْدُكَ، وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ، أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ، أَبُوءُ لَكَ بِنِعْمَتِكَ عَلَيَّ، وَأَبُوءُ لَكَ بِذَنْبِي فَاغْفِرْ لِي؛ فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ.

Q (1227) What is Sayyid al-Istighfār?
A (1227) "Allāhumma anta Rabbī, lā ilāha illā Anta, khalaqtanī wa-anā ʿabduka, wa-anā ʿalā ʿahdika wa-waʿdika mā istaṭaʿtu. Aʿūthu bika min sharri mā ṣanaʿtu. Abūʾu laka biniʿmatika ʿalayya, wa-abūʾu laka bithanbī fa-ghfir lī; fa-innahu lā yaghfiru ath-thunūba illā Anta" (O Allāh, You are my Lord; there is no god except You. You created me and I am Your slave, and I remain upon Your covenant and promise as much as I am able. I seek refuge in You from the evil of what I have done. I acknowledge before You Your favor upon me, and I acknowledge my sin to You, so forgive me; for none forgives sins except You).

Source: Kanz al-Aṭfāl.

لا إله إلا الله.
حلاوة هذا الدعاء لا توصف.

Note: the translation is deliberate. Each term is picked after careful review. Just in case you find some of my choices don't get along with the common view.