These few prayers are taken from the Roman Missal. As the official prayers of the Church, they are to be preferred to any private devotions. They are all enriched with indulgences.
Prayer of St. Thomas Aquinas before Communion
Almighty and eternal God, behold, I approach the Sacrament of Thine only-begotten Son, our Lord Jesus Christ. I approach as one who is sick to the physician of life, as one unclean to the fountain of mercy, as one blind to the light of eternal brightness, as one poor and needy to the Lord of heaven and earth. Therefore I beseech Thee, of Thine infinite goodness, to heal my sickness, to wash away my filth, to enlighten my blindness, to enrich my poverty, and to clothe my nakedness, that I may receive the Bread of angels, the King of kings, and the Lord of lords with such reverence and humility, with such contrition and devotion, with such purity and faith, with such purpose and intention, as may conduce to the salvation of my soul. Grant, I beseech Thee, that I may receive not only the Sacrament of the Body and Blood of our Lord, but also the fruit and virtue of this Sacrament. O most indulgent God, grant me so to receive the Body of Thine only-begotten Son, our Lord Jesus Christ, which He took of the Virgin Mary, that I may be found worthy to be incorporated with His mystical body and numbered among His members. O most loving Father, grant that I may one day contemplate for ever, face to face. Thy beloved Son, whom now on my pilgrimage I am about to receive under the sacramental veils; who liveth and reigneth with Thee God, world without end. Amen.
Prayer of St. Thomas Aquinas after Communion
I give Thee thanks, O holy Lord, Father almighty, eternal God, who hast vouchsafed, not for any merits of mine, but only out of the condescension of Thy mercy, to satisfy me a sinner, Thine unworthy servant, with the precious Body and Blood of Thy Son our Lord Jesus Christ. I pray that this Holy Communion be not to me a condemnation unto punishment, but a saving plea unto forgiveness. May it be unto me the armour of faith and the shield of good will. May it be the emptying out of my vices, the extinction of all concupiscence and lust, the increase of charity and patience, humility and obedience, and of all virtues; a strong defence against the snares of all enemies, visible and invisible; the quieting of all my evil impulses, both fleshly ghostly; a firm cleaving unto Thee, the one true God; and a pledge of a blessed destiny. And I beseech Thee, that Thou wouldst vouchsafe to bring me, a sinner, to that ineffable banquet, where Thou, with Thy Son and the Holy Ghost, art to Thy saints true light, fulness of content, eternal joy, gladness without alloy and perfect bliss. Through the same Christ our Lord. Amen.
Soul of Christ, sanctify me.
Body of Christ, save me.
Blood of Christ, inebriate me.
Water from the side of Christ, wash me.
Passion of Christ, strengthen me.
O good Jesu, hear me.
Within Thy wounds hide me.
Suffer me not to be separated from Thee.
From the malicious enemy defend me.
In the hour of my death call me,
And bid me come unto Thee.
That with Thy saints I may praise Thee.
For ever and ever. Amen.
I beseech Thee, most sweet Lord Jesus Christ, grant that Thy Passion may be to me a power by which I may be strengthened, protected and defended. May Thy wounds be to me food and drink, by which I may be nourished, inebriated and overjoyed. May the sprinkling of Thy Blood be to me an ablution for all my sins. May Thy death prove to me life everlasting, and Thy cross be to me an eternal glory. In these be my refreshment, my joy, my preservation and sweetness of heart. Who livest and reignest world without end. Amen.
Prayer before a Crucifix
Behold, O kind and most sweet Jesus, I cast myself upon my knees in Thy sight, and with the most fervent desire of my soul, I pray and beseech Thee that Thou wouldst impress upon my heart lively sentiments of faith, hope and charity, with true contrition for my sins and a firm purpose of amendment; while with deep affection and grief of soul I ponder within myself and mentally contemplate Thy five wounds, having before my eyes the words which David the prophet put on Thy lips concerning Thee: “They have pierced My hands and My feet, they have numbered all My bones” (Ps. 21:17-18).
Translation is from the St Andrew's Daily Missal. Buy your copy now from Bonaventure Publications: http://www.libers.com/sam.htm