The Pavamana prayer from the Brihadaranyaka Upanishad 1.3.28: lead me from untruth to truth, from darkness to light, from death to immortality.
The Upanishadic peace prayer 'Saha navavatu': teacher and student ask together for protection, nourishment, vigour and freedom from hatred.
A Sanskrit dhyana verse on the white-robed, moon-hued, four-armed, gracious-faced Lord, chanted to calm all obstacles before worship or study.
A well-loved Ganesha prayer: curved-trunk, great-bodied Lord of ten million suns' radiance, make all my undertakings free of obstacles, always.
The dhyana verse that leads the Vishnu Sahasranama: meditate on the white-robed, four-armed Vishnu with a gracious face, to calm all obstacles.