Other than the obvious Fennekin line. I need to make a team around Fox Stevenson.
The Fennekin line, as you said already. Some others are:
Source
Ninetales line Zoroark line Delphox line
^ Those are the only 3 that are specifically based off foxes.
You can arguably call all Eeveelutions foxes.
Bulbapedia - Pokemon by species
