I’m not sure if you would classify this as a “penance prayer” but it is a beautiful prayer:
Prayer of Trust in the Divine Mercy
Most merciful Jesus,
I turn to You in my need.
You are worthy of my complete trust.
You are faithful in all things.
When my life is filled with confusion, give me clarity and faith.
When I am tempted to despair, fill my soul with hope.
Most merciful Jesus,
I trust You in all things.
I trust in Your perfect plan for my life.
I trust You when I cannot comprehend Your divine Will.
I trust You when all feels lost.
Jesus, I trust You more than I trust myself.
Most merciful Jesus,
You are all-knowing.
Nothing is beyond Your sight.
You are all-loving.
Nothing in my life is beyond Your concern.
You are all-powerful.
Nothing is beyond Your grace.
Most merciful Jesus,
I trust in You,
I trust in You,
I trust in You.
May I trust You always and in all things.
May I daily surrender to Your Divine Mercy.
Most Blessed Virgin Mary, Mother of Mercy,
Pray for us as we turn to you in our need.
Act of Contrition
O my God,
I am heartily sorry for having offended Thee,
and I detest all my sins,
because I dread the loss of heaven, and the pains of hell;
but most of all because they offend Thee, my God,
Who are all good and deserving of all my love.
I firmly resolve, with the help of Thy grace,
to confess my sins, to do penance,
and to amend my life.
Amen.
