E. Stanley Jones - One of the greatest Christian missionaries and writers ever. His works would be a great set of resources.
Maxie Dunnam - probably the foremost United Methodist evangelical leader today. Retired president of Asbury Seminary. One of the most popular Christian writers among Methodists.
David Seamands - Everything he wrote was outstanding. No one better on pastoral counseling.
Robert Coleman - His "Master Plan of Evangelism" is the classic work on making disciples. No one knows more about evangelism.
Albert Outler - especially his new edition of Wesley's Works
Thomas Oden - Outstanding theologian.
Ken Kinghorn - Great church history scholar. Also wrote a great book on the Fruit of the Spirit.
John Oswalt - One of the world's best OT scholars. A number of his commentaries are published in Logos. There are other things such as his book on Malichi that are great.