Manchester City fans sing (?) (More like shout) the refrain from "Blue Moon". Definitely not folk. It doubles as a triumphal hymn when things go well on the field and as a defiant song of support when things go sideways

My favourite one (I think it came from West Ham supporters,) regarding a forward who always seemed to shoot over the bar

"When you sit in row z
And a ball hits our head
that's Zamora"