and Shadow 
That leaves for this year:
Checkered
Custard
Glowing
Invisible
Maractite
Relic
Sketch
Snot
Split
Sponge
Transparent
Woodland
Transparent might be interesting, if only because so far only one pet comes in it. Woodland might also be nice; I can just see them using leaves for their neck ruff. I'm not sure how well Relic would work, though they could be amusing. Checkered might be okay, though this largely depends on the artist, and Split is generally not something to get excited over. Glowing is not much to talk about usually, and Invisible is pretty much good only for those who do not want to look at the pet. Sketch lost a lot after the revamp as did Sponge. Custard and Snot are Custard and Snot.
Thoughts, hopes, desires?