There are also named rats here that go by the name of Flotsam and Jetsam. One or both sometimes have Shiny Golden Coin ( +MANA +CHA ) and Rat Tail ( Whip ). I forget the other specifics.
I saw Jetsam wandering around the D.C. zone. I had been killing rats and snakes trying to get rares to spawn, and this guy popped up. It took a long time to get him to come out though, probably 2 hours of killing with my 38th level bard. So he is fairly rare.