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 beloved prayer for the happiness, health and welfare of all beings, that none may suffer, closed with a threefold 'Shanti'.
The Isha Upanishad, Yajurveda 40: eighteen mantras on seeing the Lord in all things, enjoying through renunciation, and joining knowledge with action.