Here is a Byzantine prayer of thanksgiving after communion.
I give thanks to you, O Lord my God, for you have not rejected me a sinner, but have made me worthy to share in your sanctifying mysteries. I thank you for having granted that I, unworthy as I am, be a partaker of these pure and heavenly gifts. O Lord and lover of mankind who died and are risen for us, who gave us these dread and life-giving mysteries for the good of our bodies and the sanctification of our souls: make them serve for the healing of my soul and body, that they may set to flight every foe. Enlighten the eyes of my heart; give peace to the powers of my mind; inspire me with a faith in which there is no shame, a sincere love, a deep wisdom and obedience to your Commandments. May they increase in me your divine grace, and make me dwell in your kingdom. Being preserved by them in your holiness, I will remember your love at all times. From now on, I will not live for myself, but for you, my Lord and benefactor. And thus having spent my earthly life in the hope of life without end, I will one day reach eternal rest where the sound of rejoicing never ceases, where the delight of those who look upon the beauty of your face has no bounds. For you are truly the object of our desire and the inexpressible joy of those who love you, Christ our God, and all creatures glorify you forever and ever. Amen.