The following beers are typical examples of beers from the North of England;
Timothy Taylor Landlord - a pale ale with much hoppiness and bitterness.
Black Sheep Black Sheep Ale - A bitter brown beer. This is what represents the stereotypical Northern bitter for me.
Coniston Bluebird - A pale ale with a floral hoppiness.
Moorehouses Black Cat - A dark, malty mild ale.
Sam Smith's Old Brewery Pale Ale - a light brown bitter.
I'm choosing them as good examples in that they are widely available and are widely enjoyed. This is not intended as a review of them necessarily.