Saint Padre Pio prayed daily to Our Lady of Grace at San Giovanni Rotondo, Italy. You can view the image of Our Lady of Grace and read more about it here.
O heavenly treasurer of all graces, Mother of God and my mother Mary, since you are the first-born daughter of the Eternal Father and hold in your hands his omnipotence, be moved to pity my soul and grant me the graces which I fervently ask of you.
O merciful dispenser of divine graces, Mary most holy, mother of the Eternal incarnate Word who has crowned you with his immense wisdom, look upon the greatness of my sorrow and grant me the graces I need so much.
O most loving dispenser of divine graces, immaculate Spouse of the Eternal Holy Spirit, most holy Mary, who have received from him a heart which is moved to pity by human misfortunes and which is constrained to offer consolation to those who suffer, be moved to pity my soul and grant me whose graces which I await from you with full confidence in your immense goodness.
O my mother, treasurer of all graces, refuge of poor sinners, consolation of the afflicted, hope of those who despair and most powerful help of Christians, I places all my confidence in you, being sure that you will obtain for me from Jesus the graces which I so much desire, if they are good for my soul.