I expect WSYWIG to wade in here presently and set you pretty well up in that department; I could be wrong, but I generally regard her as the Resident Expert hereabouts in the area of Gospel & Praise Music.

Are we talking contemporary or "traditional" material here, or does it matter? Upbeat or worshipful?

Some of the 20-some year old Gaither material has long been a blessing to me and many others; there are the short but somewhat redundant "Praise Choruses" popular in some Fellowships these days, and for the more traditionalist there are always the timeless Fanny Crosby Hymns of the early 20th Century.
Personally, I am rather partial to some of the early to mid 19th Century works, and have accumulated a fair collection of them.
Just finished singing "Wayfaring Stranger", which always seems to move me somehow, and recently purchaced a CD of the Boston Cameratta singing Hymns of the late 1700's to 1870's, ("Trav'ling Home")mostly in tight part harmony as those old tunes were intended to be sung, and I have just fallen in love with it. Several of the songs they do on the CD are from books copies of which I have in my collection.

Some of my favorite "Campfire" Gospel tunes which are familiar and well suited to the guitar include:

Kumbaya (I wrote some alternative lyrics for it)
In The Garden
, Magic Penny
Come, Holy Spirit
His Name is Wonderful
Lights Along the Shore
Amazing Grace (Obligatory, isn't it?) I usually end a session or performance on this one.

No doubt many more will follow. Blessings abundant!