O Lord Christ, God, King of the Ages, and Maker of all men, I thank thee for all the good things which thou hast bestowed upon me, and for this Communion of thy most pure and life-giving Mysteries. Therefore I entreat thee, O Good One who lovest mankind, keep me in thy tabernacle and under the shadow of thy wings; and grant that, with a pure conscience, even unto my uttermost breath, I may worthily partake of thy Holy Things, unto the remission of my sins, and unto life eternal. For thou art the Bread of Life, the Fountain of all holiness, the Giver of good things; and unto thee we ascribe glory, to the Father, and to the Son, and to the Holy Spirit, now, and ever, and unto ages of ages. Amen.
From Isabel Florence Hapgood, Service Book of the Holy Orthodox-Catholic Apostolic Church, Houghton Mifflin, 1906, the Post-Communion Prayers, p. 123. The book itself — public domain.
Where these come from. Every prayer here is transcribed from a printed book that is out of copyright, and each one says which book and where in it. That is not fussiness. An English translation of an Orthodox prayer is a copyrighted work in its own right, separately from the Greek or Slavonic behind it, and in 2012 a monastery took a bishop to federal court for putting its translations on a website — and won. So these come from Hapgood's Service Book of 1906 and Shann's Euchology of 1891 and Book of Needs of 1894, which anyone may reprint. More on the sources and what is missing.