O Allah, You are the Pardoner, You love pardon, so pardon me. (Best du'a for Lay — Forgiveness
اللَّهُمَّ إِنَّكَ عَفُوٌّ تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي
Transliteration: Allaahumma innaka 'afuwwun tuhibbul-'afwa fa'fu 'annee
Translation: O Allah, You are the Pardoner, You love pardon, so pardon me. (Best du'a for Laylat al-Qadr)
Reference: Tirmidhi 5:534