I like naming animals after characters in books or shows that I like. Our dog is Princess Leia (just Leia most times), our cats are Philip J. Fry (Fry) and Amy Wong (Amy) from the show Futurama, and my horse is Éowyn from Lord of the Rings.
The exceptions are the miniatures whose registered names just stuck and nothing else seemed to work, Thundercloud (Cloudy) and Justabelle (Jaybee). And Pepper the dog. My husband came up with that one. It actually suits her really well, as she's kind of black and brown with a little bit of grey just like the colours in a real pepper shaker.