Agree with most mentioned above:
Band Played Waltzing Matilda
No Man's Land
Mothers, Daughters, Wives
Dancing At Whitsun
With God on Our Side
Where Have All the Flowers Gone
And many others - Add:
Rosemary's Sister by Huw Williams
When Princes Meet by Tom Paxton
Dead Girl of Hiroshima (I Come and Stand at Every Door) by
Nazim Hikmet and James Waters
Just a Roll of the Drum as done by Fairport Convention
Writing of Tiperary by B. Caddick
And on a lighter side, Take Off Your Clothes by Mark Levy
Would make a great album