In many churches, the "forgotten people" are the missionaries who represent us on foreign fields, faithfully sharing Christ far from home.
Prayers for the Faithful (B&H Books) by Mary Ann Bridgwater is a devotional and prayer resource to help you incorporate meaningful prayer for missionaries into your own prayer time. Preachers in particular will be drawn to the many powerful stories of how God has used career and short-term missionaries in reaching people for Christ.