The following formulas have been mentioned by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him) and contain great benefit:

أَسْتَغْفِرُ اللهَ لِما يَعْلَمُهُ الله أَسْتَغْفِرُ اللهَ كَما يُحِبُّهُ الله

Astaghfirullah lima ya`lamuhu Allah, Astaghfirullah kama yuhibbuhu-llah

I seek the forgiveness of Allah for everything that He knows; I seek Allah’s forgiveness in the way that He loves.

أَسْتَغْفِرُ اللهَ ذا الجَلالِ و الإِكْرَام مِنْ جَميعِ الذُّنوبِ و الآثام

Astaghfirullah dha’l-Jalali w’al-Ikram min jami` adhunubi wa’l-atham.

I seek the forgiveness of Allah, the Possessor of Majesty and Honour, for all my sins and wrongdoings.

أَسْتَغْفِرُ اللهَ الَّذِي لا إِلَهَ إِلاّ هُوَ الرَّحْمَنَ الرَّحِيمَ الْحَيَّ الْقَيُّومَ الَّذِي لا يَمُوتُ وَأَتُوبُ إِلَيْه رَبِّ اغْفِرْ لِي

Astaghfirullah alladhi la ilaha illa huwa arrahman arrahim al-Hayya al-Qayyum alladhi la yamutu wa atubu ilayhi rabbi-ghfir li

I seek the forgiveness of Allah, there is no deity but Him; the Most Compassionate, the Most Merciful, the Living, the Sustainer, the One Who never dies and I repent to Him. O Lord, forgive me.