Most popular transformations are wolf/werewolf, fox, cat, pig, dragon, and dog. Other common ones include donkeys and horses, but feel free to make up any majestic creatures from your imagination.
Make a request for whatever you would like, whether that is human-to-animal or animal-to-human. Make sure you include whether you want it human-like (anthro), or completely non-human. Include your option of female TF or male TF if you like. Have your furry or mammal transformation any specific way you like by ordering a custom.