In distress (the dua of Yunus ﷺ)
لَا إِلَهَ إِلَّا أَنْتَ سُبْحَانَكَ إِنِّي كُنْتُ مِنَ الظَّالِمِينَ
La ilaha illa anta subhanaka inni kuntu minaz-zalimin
“There is no deity except You; glory be to You. Indeed, I have been of the wrongdoers.”
Qur'an 21:87Good in both worlds
رَبَّنَا آتِنَا فِي الدُّنْيَا حَسَنَةً وَفِي الْآخِرَةِ حَسَنَةً وَقِنَا عَذَابَ النَّارِ
Rabbana atina fid-dunya hasanah, wa fil-akhirati hasanah, wa qina 'adhaban-nar
“Our Lord, give us good in this world and good in the Hereafter, and protect us from the punishment of the Fire.”
Qur'an 2:201The chief of seeking forgiveness (Sayyid al-Istighfar)
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 بِذَنْبِي، فَاغْفِرْ لِي فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ
Allahumma anta Rabbi, la ilaha illa anta, khalaqtani wa ana 'abduk, wa ana 'ala 'ahdika wa wa'dika mas-tata't, a'udhu bika min sharri ma sana't, abu'u laka bi ni'matika 'alayy, wa abu'u bi dhanbi, faghfir li fa innahu la yaghfirudh-dhunuba illa ant
“O Allah, You are my Lord, there is no deity but You. You created me and I am Your servant; I keep Your covenant and pledge to You as best I can. I seek refuge in You from the evil I have done. I acknowledge Your favour upon me and I acknowledge my sin, so forgive me, for none forgives sins except You.”
Sahih al-Bukhari