Did you read the "Borribles" trilogy by Michael De Larrabeiti? The titles of the books are "The Borribles", "The Borribles Go for Broke" and "Across the Dark Metropolis". The trilogy is slightly different from the usual fantasy though, Actually I find the usual fantasy pretty boring; in the end the prince always saves the country and gets the princess, more or less.
Ursula K. Le Guin's "Left Hand of Darkness" is on the borderline between Fantasy and SF; definitely worth reading. it is VERY different. Only partially urban though because the two main characters have to flee across the country in a large part of the book.
And try the books of Walter Moers; he is even weirder than Pratchett. I am not sure all of them have been translated into English though, but at least "The City of Dreaming Books" has.