An Australian Football League team song is traditionally sung by members of the winning team after an AFL game. Additionally, team songs are played when each team runs out onto the field prior to the beginning of the match.
The first team song was the Collingwood song "Good Old Collingwood Forever", written by player Tom Nelson in 1906 to the tune of "Goodbye, Dolly Gray", an American music hall song. Other clubs have continued to rewrite other songs' lyrics to suit their team, with very few songs having both original lyrics and music.
References
List of Australian Football League team songs Wikipedia(Text) CC BY-SA