Just to mention a few,

How High's the Watergate (Phil Ochs) - Five Feet High and Rising
And Lovin' You (Tom Paxton & Bob Gibson) - Norwegian Wood
Getting Up Early (Tom Paxton & Bob Gibson) - Mr Tamburine Man
I Can't Escape (John Denver) - Leaving on a Jet Plane; Blowin' in the Wind; Games People Play

And...

I Hear America Singing (Shel Silverstein):
Drink With Thine Eyes
Auld Lang Syne
Itsy Bitsy Spider
Mercedes Benz
Take Me Out to the Ball Game
Oh Say Can You See
Nearer My God to Thee
Sh-boom Sh-boom
...and at least 10 more.