Resources with sample mealtime or banquet invocations appropriate for luncheons include Xavier University's Jesuit resource center, Prayer-and-Prayers.info and the Rotary5960.org. Books with appropriate prayers include "100 Graces: Mealtime Blessings" by Marcia and Jack Kelly.
The Xavier Jesuit resource center's website provides a list of mealtime and banquet invocations taken from a range of sources, such as the Canadian Conference of Catholic Bishops, Mother Teresa and various Christian authors. The website also includes several non-Christian invocations, including traditional Native American, Sufi and Tibetan blessings.
Prayer-and-Prayers.info provides a number of non-denominational Christian meal blessings.
The Rotary District 5960 website provides mealtime invocations assembled by Rotary members that reflect various religions and denominations.
"100 Graces: Mealtime Blessings" features invocations from numerous religious traditions.