I have put together some sayings of the Fathers about repentance together with some psalms, canons and hymns. The following extract shows a few prayers of repentance which I find helpful and so have become favourites:
by Saint Seraphim of Sarov
A prayer of repentance (‘of St Antioch’)
Trusting, O Lord, in the abyss of Thy loving-kindness, I offer to Thee this prayer from my foul mouth and my unclean lips. Remember me, for Thy holy Name wast invoked over me, and Thou hast redeemed me with the price of Thy blood; for Thou hast sealed me with the betrothal of Thy Holy Spirit, and Thou hast raised me from the depth of my transgressions, that I should not be seized by the enemy.
O Jesus Christ, defend me and be my strong helper in my struggle; for I am a slave of lust, and I am assailed thereby. But do Thou not, O Lord, leave me cast to the earth and condemned by my deeds. Free me, O Lord, from the evil slavery of the prince of this world, and make me Thine own in Thy commandments. Thy Person is the way of my life, O my Christ, and the light of mine eyes. O God, Master and Lord, give me not roving eyes; dispel from me evil lust. Defend me with Thy holy arm. Let not longings and lusts overwhelm me, and give me not up to a shameless soul.
May the light of Thy presence shine in me, O Lord, lest darkness overwhelm me, and I be snatched by them that walk in the night. Do not surrender to invisible beasts, O Lord, a soul which confesseth to Thee. Do not allow Thy servant, O Lord, to be wounded by strange dogs.
Grant me to be a vessel of Thy Spirit, and make me a house of Thy Christ, Holy Father. O Guide of the lost, guide me lest I stray to the left. I long to see Thy face, O Lord. O God, guide me by the light of Thy countenance.
Grant me, Thy servant, a fountain of tears, and give Thy creature the dew of Thy Holy Spirit, lest I wither like the fig tree which Thou didst curse; and let tears be my drink, and prayer my food.
Turn, O Lord, my weeping into joy, and receive me into Thine eternal tabernacles. Let Thy mercy overtake me, O Lord, and Thy bounty encompass me, and pardon all my sins; for Thou art the true God Who pardonest transgressions. And allow not, O Lord, the work of Thy hands to be put to shame on account of the multitudes of my transgressions; but call me, O Lord, through Thine only-begotten Son, our Saviour.
And raise me who lie prostrate like Levi the publican, and quicken me who am slain by my sins, like the son of the widow.
For Thou alone art the Resurrection of the dead, and to Thee is due all glory; for ever. Amen.
Prayer for moments of despondency and despair
Master and Lord of Heaven and of earth, and King of the ages! Deign to open unto me the door of repentance; for in anguish of heart I pray to Thee, our true God, the Father of our Lord Jesus Christ, the Light of the world. Look upon me in Thy great loving-kindness, and accept my prayer. Incline Thine ear to my prayer and forgive me all the evil that I have done by the abuse of my free will. Behold, I seek rest, yet I do not find it; for I have not received forgiveness from my conscience. I thirst for peace, but there is no peace in me from the dark abyss of my transgressions. Hear, O Lord, a heart which crieth unto Thee. Regard not my evil deeds; but consider the agony of my soul and make haste to heal me who am badly wounded. By the grace of Thy love for men, give me time for repentance and deliver me from my shameful deeds. Reward me not according to Thy justice and requite me not according to my deeds, lest I finally perish.
Hear me, O Lord, in my despair. Behold, I am bereft of my will and of every thought of amendment. Therefore, I have recourse to Thy compassion. Have mercy on me, cast down and condemned on account of my sins. O Lord, rescue me who am enslaved and held by my evil deeds, as if I were shackled with chains. Thou alone knowest how to set prisoners free; and as Thou alone knowest secret things, Thou healest wounds which are known to none but seen by Thee.
Therefore, being tortured in every way by cruel pains, I cry only to Thee, the Physician of all who are afflicted, the Door of them that knock without, the Way of the lost, the Light of them in darkness, the Redeemer of those in bonds, Who ever restrainest Thy right hand and withholdest Thine anger prepared for sinners, but Who givest time for repentance through Thy great love for men.
O Thou Who art quick to show mercy and slow to punish! – shine upon me, who have fallen badly, the light of Thy countenance, O Lord. And in Thy loving-kindness, stretch out Thy hand to me and raise me from the depth of my transgressions.
For Thou alone art our God, Who dost not rejoice at the destruction of sinners, and Who dost not turn Thy face away from them that cry unto Thee with tears.
Hear, O Lord, the voice of Thy servant who crieth unto Thee; and manifest Thy light to me who am deprived of light. And give me Thy grace, for I have no hope whatever, that I may always trust in Thy help and power. Turn my weeping into joy, rend my rags, and gird me with Thy gladness.
And grant that I may rest from my dark deeds, and enjoy the morning calm with Thy chosen, O Lord, whence all pain, sorrow and sighing have fled away. And may the door of Thy Kingdom be opened unto me, that I may enter with them that rejoice in the light of Thy countenance, O Lord, and that even I may receive eternal life in Christ Jesus our Lord. Amen.
FURTHER PENITENTIAL PRAYERS
From the Great Book of Needs
O Lord God of righteousness, my strength and my help, my refuge in evil days; Thou Who savest in times of sorrows: do Thou save me, for the waters have come in to my soul; I have sunk into a muddy abyss, and there is no standing before the face of the violent enemy. For my soul is pursued, my life is trampled down to the ground, and all night long the toll-keepers assail me. Be well pleased, O Lord, to deliver me from the hands of transgressors and them that do wrong, that I sin not against Thee. For the terrors of death have fallen upon me, and darkness covereth me. How long shall I cry unto Thee, O Lord, and Thou hearest not? Wounded, I call out unto Thee, and Thou dost not save. Look down from Heaven, O Lord, and consider from Thy holy house, where is Thy glory; for Thou hast shewn mercy to us according unto Thy mercies. O Lord, do Thou judge them that assail me: be not as a man that sleepeth, nor as a man not able to save. For Thou art a merciful God Who lovest mankind, and unto Thee do we send up glory: to the Father, and unto the Son, and unto the Holy Spirit, now and ever, and unto ages of ages. Amen.