Worcester Warriors in the Rugby as I lived there for a few years
Oakland Athletics in Baseball and Vancouver Whitecaps in MLS as my Sister lived there and it's a great city
Sussex CCC, Washington Redskins, Kansas City Royals (technically, although I never watch baseball), whatever team in F1 has a Japanese driver (none at present ), Europe in the Ryder Cup.
Sussex CCC - cricket
Boston Red Sox - baseball
And I'm developing a bit of an interest in the: Boston Bruins - ice hockey.
It's actually a really good sport although, given what extraordinary athletes ice hockey players are, how come they all look like they have a smack habit?
I did once pretend to support Natal rugby team but that was only because I was living in Phalaborwa in the north of South Africa and it was full of Afrikaaners* who gave me grief for being English and loving a 'black man's game' rather than rugby and they were North Transvaal fans and don't like Natal because it's full of English people.
*I have met some lovely Afrikaaners in my time but they tended not to be pig ignorant inbred miners from a Hicksville town on the edge of a Safari park. They ironed their jeans down the middle for Christ's sake, And they only have about 12 surnames. A tell-tale sign that something isn't right.