Please always remember to pray for the souls in Purgatory. Below is the Prayer of St. Gertrude, which is a powerful prayer to pray every day if you can:

Eternal Father,
I offer Thee the Most Precious Blood of Thy Divine Son, Jesus,
in union with the Masses said throughout the world today,
for all the Holy Souls in Purgatory,
for sinners everywhere,
for sinners in the Universal Church,
those in my own home and within my family.
Amen.

Here is another beautiful prayer for these souls:

O gentle Heart of Jesus, ever present in the Blessed Sacrament, ever consumed with burning love for the poor captive souls in Purgatory, have mercy on them.
Be not severe in Your judgments, but let some drops of Your Precious Blood fall upon the devouring flames.
And, Merciful Saviour, send Your angels to conduct them to a place of refreshment, light and peace.
Amen.