Here is a prayer by Fr. Paul Virnig (St. Cloud Diocese Rural Life 1950s) that you might consider putting on your list:
PRAYER FOR RAIN: "Almighty God, we need rain. We realize now, looking up into the clear blue sky, what a marvel even the least drop of rain really is. To think that so much water can fall out of the sky, which is now empty and clear. We place our trust in You. We are sure that You know our needs, but You want us to ask anyway, to show You that we know we are dependent on You. Look on our dry hills and fields, dear God, and bless them with the living blessing of soft rain. Then the land will rejoice, and the rivers will sing your praises, and the hearts of all will be made glad. Amen."