O Allah, I am fasting and I ask You from Your bounty. — Fasting
اللَّهُمَّ إِنِّي صَائِمٌ وَأَسْأَلُكَ مِنْ فَضْلِكَ
Transliteration: Allaahumma innee saa'imun wa as'aluka min fadlik
Translation: O Allah, I am fasting and I ask You from Your bounty.
Reference: General supplication