In my experience of playing gospel music, here is your main arsenal of chords for any key:
Chord built off 1st scale degree = major (1-3-5)
Chord built off 2nd scale degree = minor (2-4-6)
Chord built off 3rd scale degree = minor (3-5-7)
Chord built off 4th scale degree = major (4-6-1)
Chord built off 5th scale degree = major (5-7-2)
Chord built off 6th scale degree = minor (6-1-3)
Chord built off 7th scale degree = diminished (7-2-4)
If you experiment w/ using those chords with your bass notes, you should be straight on most songs. You can also add notes to these chords to come up with even more chords. So, get our your pencil, paper, and keyboard and get to experimenting!!!