Prayer to Jesus Christ for the Holy Souls by Saint Alphonsus Liguori

O most sweet Jesus, through the bloody sweat which Thou didst suffer in the Garden of Gethsemane, have mercy on these Blessed Souls. Have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the pains which Thou didst suffer during Thy most cruel scourging, have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the pains which Thou didst suffer in Thy most painful crowning with thorns, have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the pains which Thou didst suffer in carrying Thy cross to Calvary, have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the pains which Thou didst suffer during Thy most cruel Crucifixion, have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the pains which Thou didst suffer in Thy most bitter agony on the Cross, have mercy on them.
R. Have mercy on them, O Lord.

O most sweet Jesus, through the immense pain which Thou didst suffer in breathing forth Thy Blessed Soul, have mercy on them.
R. Have mercy on them, O Lord.

(Recommend yourself to the Souls in Purgatory and mention your intentions)

Blessed Souls, we have prayed for thee;
we entreat thee, who are so dear to God,
and who are secure of never losing Him,
to pray for us miserable sinners,
who are in danger of being damned,
and of losing God forever.

Let us pray:

O God, the author of mercy,
the lover of the salvation of mankind;
we address thy clemency, in behalf of our brethren, relations, and benefactors,
who are departed this life, that by the intercession of Blessed Mary,
ever Virgin, and of all the saints,
thou wouldst receive them into the enjoyment
of eternal happiness; through Christ our Lord. Amen. Source: EWTN

Litany for the Poor Souls in Purgatory

O Jesus, Thou suffered and died that all mankind might be saved and brought to eternal happiness.  Hear our pleas for further mercy on the souls of:

My dear parents and grandparents, my Jesus mercy!
My brothers and sisters and other near relatives, my Jesus mercy!
My godparents and sponsors of confirmation, my Jesus mercy!
My spiritual and temporal benefactors, my Jesus mercy!
My friends and neighbors, my Jesus mercy!
All for whom love or duty bids me pray, my Jesus mercy!

Those who have offended me, my Jesus mercy!
Those who have suffered disadvantage or harm through me, my Jesus mercy!

Those who are especially beloved by Thee, my Jesus mercy!
Those whose release is near at hand, my Jesus mercy!
Those who desire most to be united to Thee, my Jesus mercy!

Those who endure the greatest sufferings, my Jesus mercy!
Those whose release is most remote, my Jesus mercy!
Those who are least remembered, my Jesus mercy!

Those who are most deserving on account of their services to the Church, my Jesus mercy!
The rich, who now are the most destitute, my Jesus mercy!
The mighty, who now are powerless, my Jesus mercy!
The once spiritually blind, who now see their folly, my Jesus mercy!
The frivolous, who spent their time in idleness, my Jesus mercy!

The poor, who did not seek the treasures of heaven, my Jesus mercy!
The tepid, who devoted little time to prayer, my Jesus mercy!
The indolent, who neglected to perform good works, my Jesus mercy!
Those of little faith, who neglected the frequent reception of the Sacraments, my Jesus mercy!
The habitual sinners, who owe their salvation to a miracle of grace, my Jesus mercy!

Parents who failed to watch over their children, my Jesus mercy!
Superiors who were not solicitous for the salvation of those entrusted to them, my Jesus mercy!
Those who strove for worldly riches and pleasures, my Jesus mercy!
The worldly-minded, who failed to use their wealth and talents in the service of God, my Jesus mercy!
Those who witnessed the death of others, but would not think of their own, my Jesus mercy!

Those who did not provide for the life hereafter, my Jesus mercy!
Those whose sentence is severe because of the great things entrusted to them, my Jesus mercy!

The popes, kings, and rulers, my Jesus mercy!
The bishops and their counselors, my Jesus mercy!
My teachers and spiritual advisors, my Jesus mercy!
The deceased priests of this diocese, my Jesus mercy!
The priests and religious of the Catholic Church, my Jesus mercy!

The defenders of the holy faith, my Jesus mercy!
Those who died on the battlefield, my Jesus mercy!
Those who fought for their country, my Jesus mercy!
Those who were buried in the sea, my Jesus mercy!
Those who died of apoplexy, my Jesus mercy!

Those who died of heart attacks, my Jesus mercy!
Those who suffered and died of cancer, my Jesus mercy!
Those who died suddenly in accidents, my Jesus mercy!
Those who died without the last rites of the Church, my Jesus mercy!
Those who shall die within the next twenty-four hours, my Jesus mercy!
My own poor soul when I shall have to appear before Thy judgment seat, my Jesus mercy!

Eternal rest grant unto them, O Lord, and let perpetual light shine upon them: Forevermore with Thy saints, because Thou art gracious.

May the prayer of Thy suppliant people, we beseech Thee, O Lord, benefit the souls of Thy departed servants and handmaids: that Thou mayest both deliver them from all their sins, and make them to be partakers of Thy redemption. Amen.

Eternal rest grant unto them, O Lord.
And let the perpetual light shine upon them.
May their souls and the souls of the faithful departed, through the mercy of God, rest in peace. Amen.