bat
bat-ball
basketball
basilisk
baseball
bart
baratheon
banana
badger
bad-clover
bad-boy
athletic
astronaut
army
aries
archer
arachno-kid
aqua
april-fool
apple
apocalypse-rider
angry
amber
amazed
alien-x
alien-tree
alaska
alabama
air-bag
aer
acorn
Here is a list with all custom skins.
You can use these images urls with extensions like Ogario and Agartool.