Pretty much depends on the age group. See these threads:
https://www.acousticguitarforum.com/...d.php?t=428015
https://umgf.com/the-dreaded-campfir...50394-s20.html
55 years ago, when I was the only guitar-playing counselor at a summer camp, one evening I instantly became the de-facto campfire song leader. I learned some of the above lessons real fast. I am now an old guy. In addition to the entire PPM/Kingston Trio and PPM repertoire, I'll submit a few for your consideration....including a couple most guitar players never want to hear again:
FAMILY CAMPFIRE:
WILL YOU LOVE ME TOMORROW
WAGON WHEEL
YOU AINT GOIN' NOWHERE
RAPID ROY
ROLLER DERBY QUEEN
IN THE JAILHOUSE NOW
CHAINS
GOIN' STEADY
MOTEL COWBOY
NIGHT RIDER'S LAMENT
LATE NIGHT RADIO
SAN FRANCISCO BAY BLUES
COWBOY BUCKAROO
When they are all worn out: TODAY
If they are pleasantly buzzed and sentimental:
ROSEVILLE FAIR and GOIN' GONE
If you're out in the woods: PONIES
For Boomer sing-alongs:
Most anything by The Beatles (early tunes)
Brown Eyed Girl
Take It easy
Hey Baby
Folkified versions of Heat Wave
ADULT CAMPFIRE:
IT DOESN'T PAY TO BE HIP
WHY DON'T WE JUST DANCE?
STACY BROWN GOT TWO
SHAME AND SCANDAL
BIG BALL'S IN COW TOWN
BUCKO'S MEMOIRS
LET'S TALK DIRTY IN HAWAIIAN
THIRD RATE ROMANCE