Also:
http://urdb.kirlad.net/index.php
A database with all the new characters as they are added to the series, plus their evolutions.
They also have a deviantart page:
http://urban-rivals.deviantart.com/
They only show one stage of each new character on the devart page. But favoriting them is a great way to get quick updates on when they add new characters to the series.