North American Mission Handbook: U.S. and Canadian Protestant Ministries Overseas edited by Peggy Newell
Mission Handbook contains information on nearly one thousand agencies working overseas. Aside from the agency listings with contact information, types of mission activities, areas of service, personnel statistics, and more, the agencies are also listed by church tradition, by ministry activities, and by country of activity.
Ask a Missionary has a series of questions and answers on topics related to support choosing a sending agency.
The Mission Finder website contains a search function to help prospective missionaries find an organization or a trip that matches their interests and giftings.
A British organization, OSCAR has a comprehensive list of missions organizations with a UK base of representation.
Mission Next works to connect Christians with missions opportunities that will match their interests and skills.
Below are listed some specific mission organisations which have been recommended:
Shepherd's Staff Mission Facilitators provide administrative services for support funds and access to missionary group health plan and 403b retirement plan.
OMF International (formerly China Inland Mission and Overseas Missionary Fellowship) have a wide variety of ministry opportunities throughout East Asia.
World Outreach Ministries provides logistical support and processing of donations to independent missionaries.
Equip International serves as a parent organization to missionaries serving in fourteen countries.
Saving Grace World Mission assists their missionaries with financial accountability and donor records, cross-cultural training, and communicating with ministry partners.
Action International has opportunities for short, mid, and long term service in 30 different countries.
Frontiers works to "fulfil the Great Commission among Muslim people groups that don't know the saving message of Jesus Christ."