There is a lorica prayer written probably sometime in the 8th century, around the same time that the familiar prayer known as "St. Patrick's Breastplate" or "The Deer's Cry" was composed. It feels remarkably Pagan, despite its date. With very little editing, it can be made entirely Pagan. I offer this translation, from John Carey's King of Mysteries: Early Irish Religious Writings. It is called Cétnad n-Aíse: A Chant of Long Life, or Fer Fio's Cry.
May Fer Fio's cry protect me upon the road, as I make my circuit of the Plain of Life.
I invoke the seven daughters of the sea
who form the threads of the long-lived youths.
May three deaths be taken from me,
may three life-times be granted me,
may seven waves of luck be poured out for me.
May spectres not harm me upon my rounds
in the breastplate of Laisrén, without injury.
My fame is not bound to perish.
May long life come to me,
may death not come to me
until I am old.
I invoke my silver warrior,
who has not died, who will not die.
May time be granted me
with the virtue of findruine.
May my shape be made golden,
may my rank be ennobled,
may my strength be magnified.
May my burial be not swift,
may death not come to me upon the road,
may my journey be confirmed.
May the senseless snake not sieze me,
nor the harsh grey worm,
nor the senseless beetle.
May no thief destroy me,
nor a company of women,
nor a company of warriors.
May an extension of time be granted me by the King of all things.
I invoke Senach of the seven ages,
whom fairy women fostered
on the breasts of inspiration.
May my seven candles be not quenched.
I am an impregnable fortress,
I am an immovable rock,
I am a precious stone,
I am a weekly blessing.
May I live a hundred times a hundred years,
each hundred of them in turn.
I summon their benefits to me;
may the grace of the holy spirit be upon me.
May all who are fighting for justice and equity in these difficult times be protected. May they be blessed. May their strength be magnified. May they be an impregnable fortress and an immovable rock. My heart is with you, even though my body cannot be.