How 'bout them cowboys is great because you can always throw it back at them. Who dat/dey is definitely one of the worse. Not so much bandwagon fans but I'm a grammar w****.
That's not really a chant, it's the last line of their fight song but it is the part said with most emphasis.
Not limited to any single sport...and not a normal slogan that belongs to any particular team...although all opponents seem to use this... "Houston...you have a problem"
The titans. They don't really have a slogan, but I hate them more than I hate any other team slogan. The whole team and all their backward inbreeding fans can ROT IN HELL for all I care. And I say that with the greatest of respect.