This is the prayer that was on the card from the Marianist Mission my mother sent me for Thanksgiving:
Good and gracious God, we come before You today united with all who give You thanks and praise. Fill us with gratitude for Your many blessings, both physical and spiritual.
We thank You in particular this day for the gifts of food and family. Bless this food, Lord, that it may nourish our bodies. Bless our family, especially those who can't be with us today. Also today, we remember those of our family who have gone to be with You.
Grant us Your spiritual blessings and help us pray daily for the grace to serve You in response to Your bountiful gifts to us. Bless all who serve You throughout the World.
We pray this in the name of Jesus, Your Son, Our Lord, who gives all things freely according to our needs. Continue to bless us and give us Your peace. Amen.